diff --git a/.clang-format b/.clang-format
index db481b97..24714372 100644
--- a/.clang-format
+++ b/.clang-format
@@ -42,6 +42,8 @@ EmptyLineBeforeAccessModifier: Leave
 FixNamespaceComments: false
 IncludeBlocks: Regroup
 IncludeCategories:
+  - Regex: '^"platform\.hpp"$'
+    Priority: -1
   - Regex: '^<sys/'
     Priority: 0
   - Regex: '^<'
diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index a0f2f28a..054e7038 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -371,8 +371,12 @@ jobs:
             python312-imaging
       - name: Build using Make
         if: matrix.arch == 'x86'
-        run: | # Cygwin doesn't support `make develop` sanitizers ASan or UBSan, so we don't use it.
-          make -k -j "$(getconf _NPROCESSORS_ONLN)" Q=
+        run: | # Cygwin doesn't support `make develop` sanitizers ASan or UBSan, so we disable them.
+          : # 32-bit Cygwin stopped updating since 2022-11-23, and its g++ 11.3.0 gives a false
+          : # positive "potential null pointer dereference" error on `patch.pcOffset -= pcShift;`
+          : # in src/asm/output.cpp, so we disable that warning option.
+          make develop -k -j "$(getconf _NPROCESSORS_ONLN)" Q= \
+               WARNFLAGS="-fno-sanitize=all -Wno-null-dereference"
       - name: Install using Make
         if: matrix.arch == 'x86'
         run: |
diff --git a/Makefile b/Makefile
index 97c6522b..e9bcc114 100644
--- a/Makefile
+++ b/Makefile
@@ -222,7 +222,7 @@ install: all
 # continous integration infrastructure return failure.
 # The rationale for some of the flags is documented in the CMakeLists.
 develop:
-	$Q${MAKE} WARNFLAGS="${WARNFLAGS} -Werror -Wextra \
+	$Q${MAKE} WARNFLAGS="-Werror -Wextra \
 		-Walloc-zero -Wcast-align -Wcast-qual -Wduplicated-branches -Wduplicated-cond \
 		-Wfloat-equal -Wlogical-op -Wnull-dereference -Wold-style-cast -Wshift-overflow=2 \
 		-Wstringop-overflow=4 -Wtrampolines -Wundef -Wuninitialized -Wunused -Wshadow \
@@ -232,8 +232,9 @@ develop:
 		-D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC -D_GLIBCXX_SANITIZE_VECTOR \
 		-D_GLIBCXX_VERBOSE_ASSERT -D_GLIBCXX_EXTERN_TEMPLATE=0 \
 		-D_LIBCPP_DEBUG -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG \
-		-fsanitize=address -fsanitize=undefined -fsanitize=float-divide-by-zero" \
-		CXXFLAGS="-ggdb3 -Og -fno-omit-frame-pointer -fno-optimize-sibling-calls"
+		-fsanitize=address -fsanitize=undefined -fsanitize=float-divide-by-zero \
+		${WARNFLAGS}" \
+		CXXFLAGS="-ggdb3 -Og -fno-omit-frame-pointer -fno-optimize-sibling-calls ${CXXFLAGS}"
 
 # Target used in development to debug with gdb.
 debug:
diff --git a/docs/CONTRIBUTING.md b/docs/CONTRIBUTING.md
index e4202200..88ca2b64 100644
--- a/docs/CONTRIBUTING.md
+++ b/docs/CONTRIBUTING.md
@@ -57,6 +57,18 @@ just modifying a file, you don't need to do anything (maybe update the copyright
 years). If you are adding new files, you need to use the
 `SPDX-License-Identifier: MIT` header.
 
+### AI usage
+
+If you are using AI to assist in writing your contribution, you must follow
+[GBDev's AI policy](https://gbdev.io/aipolicy.html). In particular, you are
+responsible for reviewing all AI-generated code, ensuring compliance with
+licensing requirements, and taking full responsibility for the contribution.
+When AI tools have meaningfully assisted in producing a contribution, you must
+disclose it with an `Assisted-by` tag in the Git commit message, as detailed
+by the policy.
+
+### Contribution steps
+
 1. Fork this repository.
 2. Checkout the `master` branch.
 3. Create a new branch to work on. You could still work on `master`, but it's
@@ -65,16 +77,18 @@ years). If you are adding new files, you need to use the
    target checks for additional warnings. Your patches shouldn't introduce any
    new warning (but it may be possible to remove some warning checks if it makes
    the code much easier).
-   
-   You can also use `cmake --preset develop` if you prefer.
+
+    You can also use `cmake --preset develop` if you prefer.
+
 5. Test your changes by running `./run-tests.sh` in the `test` directory.
    `./run-tests.sh --help` will print its available options. (You must run
    `external/fetch-repos.sh` first; if you forget to, the test suite will fail and
    remind you mid-way.)
-   
-   You can also use `ctest --test-dir build` if you prefer.
-   `ctest --test-dir build --print-labels` will print its available
-   [test labels](https://cmake.org/cmake/help/latest/manual/ctest.1.html#label-matching).
+
+    You can also use `ctest --test-dir build` if you prefer.
+    `ctest --test-dir build --print-labels` will print its available
+    [test labels](https://cmake.org/cmake/help/latest/manual/ctest.1.html#label-matching).
+
 6. Format your changes according to `clang-format`, which will reformat the
    coding style according to our standards defined in `.clang-format`. You can
    use `make format` to format all the C++ files.
@@ -133,7 +147,7 @@ its contents.
 
 ### RGBLINK
 
-Each `.asm` file corresponds to one test, or one *set* of tests.
+Each `.asm` file corresponds to one test, or one _set_ of tests.
 
 All tests begin by assembling the `.asm` file into an object file, which will be
 linked in various ways depending on the test.
diff --git a/include/file.hpp b/include/file.hpp
index a400b7a7..6c9dd583 100644
--- a/include/file.hpp
+++ b/include/file.hpp
@@ -3,6 +3,8 @@
 #ifndef RGBDS_FILE_HPP
 #define RGBDS_FILE_HPP
 
+#include "platform.hpp"
+
 #include <fcntl.h>
 #include <fstream>
 #include <ios>
@@ -12,7 +14,6 @@
 #include <variant>
 
 #include "helpers.hpp" // assume
-#include "platform.hpp"
 
 class File {
 	std::variant<std::streambuf *, std::filebuf> _file;
diff --git a/include/gfx/pal_spec.hpp b/include/gfx/pal_spec.hpp
index d19d7fe3..6cf3dcd8 100644
--- a/include/gfx/pal_spec.hpp
+++ b/include/gfx/pal_spec.hpp
@@ -4,8 +4,12 @@
 #define RGBDS_GFX_PAL_SPEC_HPP
 
 #include <stdint.h>
+#include <string>
+
+#include "gfx/png.hpp"
 
 void parseInlinePalSpec(char const * const rawArg);
+void parseEmbeddedPalSpec(Png const &png);
 void parseExternalPalSpec(char const *arg);
 void parseDmgPalSpec(char const * const rawArg);
 void parseBackgroundPalSpec(char const *arg);
diff --git a/include/gfx/process.hpp b/include/gfx/process.hpp
index d0105ff2..afa5955e 100644
--- a/include/gfx/process.hpp
+++ b/include/gfx/process.hpp
@@ -3,7 +3,9 @@
 #ifndef RGBDS_GFX_PROCESS_HPP
 #define RGBDS_GFX_PROCESS_HPP
 
+#include "gfx/png.hpp"
+
 void processPalettes();
-void process();
+void process(Png &&png);
 
 #endif // RGBDS_GFX_PROCESS_HPP
diff --git a/include/platform.hpp b/include/platform.hpp
index 89f19aaf..ab7d4fc6 100644
--- a/include/platform.hpp
+++ b/include/platform.hpp
@@ -3,6 +3,12 @@
 #ifndef RGBDS_PLATFORM_HPP
 #define RGBDS_PLATFORM_HPP
 
+// MingGW and Cygwin may need POSIX functions which are not standard C explicitly enabled
+// Make sure to keep this before any system header!
+#if (defined(__MINGW32__) || defined(__CYGWIN__)) && !defined(_POSIX_C_SOURCE)
+	#define _POSIX_C_SOURCE 200809L
+#endif
+
 // MSVC doesn't have str(n)casecmp, use a suitable replacement
 #ifdef _MSC_VER
 	#include <string.h> // IWYU pragma: export
@@ -55,17 +61,6 @@
 	#define setmode(fd, mode) (0)
 #endif
 
-// Windows has 32-bit `long`, which limits `fseek` and `ftell` to 2 GiB
-#if defined(_MSC_VER) || defined(__MINGW32__)
-	#define fseek _fseeki64
-	#define ftell _ftelli64
-#endif
-
-// MingGW and Cygwin may need POSIX functions which are not standard C explicitly enabled
-#if (defined(__MINGW32__) || defined(__CYGWIN__)) && !defined(_POSIX_C_SOURCE)
-	#define _POSIX_C_SOURCE 200809L
-#endif
-
 // Apple has deprecated `sprintf` since Xcode 14 (for macOS 13), but we use it solely in
 // contexts where both the size of the buffer *and* max size of the printed string are
 // known statically, which GCC thus checks for.
diff --git a/src/asm/fstack.cpp b/src/asm/fstack.cpp
index 7d363bc8..e00cc695 100644
--- a/src/asm/fstack.cpp
+++ b/src/asm/fstack.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp" // strncasecmp
+
 #include "asm/fstack.hpp"
 #include <sys/stat.h>
 
@@ -22,7 +24,6 @@
 #include "helpers.hpp"
 #include "itertools.hpp" // reversed
 #include "linkdefs.hpp"
-#include "platform.hpp" // strncasecmp
 #include "verbosity.hpp"
 
 #include "asm/intern.hpp"
diff --git a/src/asm/lexer.cpp b/src/asm/lexer.cpp
index 2f560217..35d6ce44 100644
--- a/src/asm/lexer.cpp
+++ b/src/asm/lexer.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "asm/lexer.hpp"
 #include <sys/stat.h>
 
@@ -27,7 +29,6 @@
 #include <vector>
 
 #include "helpers.hpp"
-#include "platform.hpp"
 #include "style.hpp"
 #include "util.hpp"
 #include "verbosity.hpp"
diff --git a/src/asm/main.cpp b/src/asm/main.cpp
index 712d81e7..a7896c0f 100644
--- a/src/asm/main.cpp
+++ b/src/asm/main.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "asm/main.hpp"
 
 #include <algorithm>
@@ -23,8 +25,7 @@
 #include "diagnostics.hpp"
 #include "helpers.hpp"
 #include "parser.hpp" // Generated from parser.y
-#include "platform.hpp"
-#include "style.hpp" // style_Parse
+#include "style.hpp"  // style_Parse
 #include "usage.hpp"
 #include "util.hpp" // UpperMap
 #include "verbosity.hpp"
diff --git a/src/asm/output.cpp b/src/asm/output.cpp
index f635c9e5..405d7ae0 100644
--- a/src/asm/output.cpp
+++ b/src/asm/output.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "asm/output.hpp"
 
 #include <algorithm>
@@ -16,7 +18,6 @@
 
 #include "helpers.hpp" // assume, Defer
 #include "linkdefs.hpp"
-#include "platform.hpp"
 #include "util.hpp" // xfclose
 
 #include "asm/charmap.hpp"
diff --git a/src/asm/section.cpp b/src/asm/section.cpp
index 5d784466..4e0f081b 100644
--- a/src/asm/section.cpp
+++ b/src/asm/section.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp" // fseek
+
 #include "asm/section.hpp"
 
 #include <algorithm>
@@ -21,8 +23,7 @@
 #include "helpers.hpp"
 #include "itertools.hpp" // InsertionOrderedMap
 #include "linkdefs.hpp"
-#include "platform.hpp" // fseek
-#include "util.hpp"     // xfclose, seekSize
+#include "util.hpp" // xfclose, seekSize
 
 #include "asm/fstack.hpp"
 #include "asm/lexer.hpp"
diff --git a/src/backtrace.cpp b/src/backtrace.cpp
index c113ca7c..245a2fc4 100644
--- a/src/backtrace.cpp
+++ b/src/backtrace.cpp
@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp" // strcasecmp
+
 #include "backtrace.hpp"
 
 #include <optional>
 #include <stdint.h>
 
-#include "platform.hpp" // strcasecmp
-#include "util.hpp"     // parseWholeNumber
+#include "util.hpp" // parseWholeNumber
 
 Tracing tracing;
 
diff --git a/src/fix/fix.cpp b/src/fix/fix.cpp
index 05a2e58b..9cf7d613 100644
--- a/src/fix/fix.cpp
+++ b/src/fix/fix.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "fix/fix.hpp"
 #include <sys/stat.h>
 
@@ -14,7 +16,6 @@
 
 #include "diagnostics.hpp"
 #include "helpers.hpp"
-#include "platform.hpp"
 #include "util.hpp" // xclose, xfclose
 
 #include "fix/main.hpp"
diff --git a/src/fix/main.cpp b/src/fix/main.cpp
index bfdcbd84..2d93b7ce 100644
--- a/src/fix/main.cpp
+++ b/src/fix/main.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "fix/main.hpp"
 
 #include <errno.h>
@@ -15,7 +17,6 @@
 #include "cli.hpp"
 #include "diagnostics.hpp"
 #include "helpers.hpp"
-#include "platform.hpp"
 #include "style.hpp"
 #include "usage.hpp"
 #include "util.hpp"
diff --git a/src/fix/mbc.cpp b/src/fix/mbc.cpp
index 5546b8c2..db8815cb 100644
--- a/src/fix/mbc.cpp
+++ b/src/fix/mbc.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp" // strcasecmp
+
 #include "fix/mbc.hpp"
 
 #include <optional>
@@ -10,8 +12,7 @@
 #include <unordered_map>
 #include <utility>
 
-#include "helpers.hpp"  // unreachable_
-#include "platform.hpp" // strcasecmp
+#include "helpers.hpp" // unreachable_
 #include "util.hpp"
 
 #include "fix/warning.hpp"
diff --git a/src/gfx/main.cpp b/src/gfx/main.cpp
index b807e12f..38dfc388 100644
--- a/src/gfx/main.cpp
+++ b/src/gfx/main.cpp
@@ -1,10 +1,13 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "gfx/main.hpp"
 
 #include <inttypes.h>
 #include <ios>
 #include <optional>
+#include <png.h>
 #include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -18,7 +21,6 @@
 #include "diagnostics.hpp"
 #include "file.hpp"
 #include "helpers.hpp"
-#include "platform.hpp"
 #include "style.hpp" // style_Parse
 #include "usage.hpp"
 #include "util.hpp"
@@ -479,6 +481,7 @@ static void parseArg(int ch, char *arg) {
 // LCOV_EXCL_START
 static void verboseOutputConfig() {
 	usage.printVersion(true);
+	fprintf(stderr, "Using libpng %s\n", png_get_libpng_ver(nullptr));
 
 	printVVVVVVerbosity();
 
@@ -524,12 +527,18 @@ static void verboseOutputConfig() {
 		break;
 	case Options::INLINE:
 	case Options::EXTERNAL:
-		fputs("\tExplicit palette spec\n\t[\n", stderr);
+	case Options::EMBEDDED:
+		if (options.palSpecType == Options::EMBEDDED) {
+			fputs("\tEmbedded palette spec from PNG indexed PLTE chunk\n", stderr);
+		} else {
+			fputs("\tExplicit palette spec\n", stderr);
+		}
+		fputs("\t[\n", stderr);
 		for (auto const &pal : options.palSpec) {
 			fputs("\t\t", stderr);
 			for (auto const &color : pal) {
 				if (color.has_value()) {
-					fprintf(stderr, "#%06x, ", color->toCSS() >> 8);
+					fprintf(stderr, "#%08x, ", color->toCSS());
 				} else {
 					fputs("#none, ", stderr);
 				}
@@ -538,9 +547,6 @@ static void verboseOutputConfig() {
 		}
 		fputs("\t]\n", stderr);
 		break;
-	case Options::EMBEDDED:
-		fputs("\tEmbedded palette spec from PNG indexed PLTE chunk\n", stderr);
-		break;
 	case Options::DMG:
 		fprintf(stderr, "\tDMG palette spec $%02" PRIx8 "\n", options.palSpecDmg);
 		break;
@@ -671,13 +677,32 @@ int main(int argc, char *argv[]) {
 	autoOutPath(localOptions.autoPalettes, options.palettes, ".pal");
 	autoOutPath(localOptions.autoPalmap, options.palmap, ".palmap");
 
+	// Read the input image now since it may be needed for parsing an embedded palette spec
+	bool useInputImage = !options.input.empty() && !localOptions.reverse;
+	Png png;
+	if (useInputImage) {
+		if (File image;
+		    image.open(options.input, std::ios_base::in | std::ios_base::binary) == nullptr) {
+			fatal(
+			    "Failed to open PNG image (\"%s\"): %s", image.c_str(options.input), strerror(errno)
+			);
+		} else {
+			png = Png(image.c_str(options.input), *image);
+		}
+	}
+
 	// Execute deferred pal spec parsing, now that all other params are known.
 	// Do not parse pal specs if `options.nbColorsPerPal` is invalid.
 	if (options.nbColorsPerPal > 0 && options.nbColorsPerPal <= 4) {
 		switch (options.palSpecType) {
 		case Options::NO_SPEC:
+			assume(!localOptions.palSpec);
+			break;
 		case Options::EMBEDDED:
 			assume(!localOptions.palSpec);
+			if (useInputImage) {
+				parseEmbeddedPalSpec(png);
+			}
 			break;
 		case Options::INLINE:
 			assume(localOptions.palSpec);
@@ -703,7 +728,7 @@ int main(int argc, char *argv[]) {
 		if (localOptions.reverse) {
 			reverse();
 		} else {
-			process();
+			process(std::move(png));
 		}
 	} else if (!options.palettes.empty() && options.hasExplicitPalSpec() && !localOptions.reverse) {
 		processPalettes();
diff --git a/src/gfx/pal_spec.cpp b/src/gfx/pal_spec.cpp
index 045881c4..f667b36a 100644
--- a/src/gfx/pal_spec.cpp
+++ b/src/gfx/pal_spec.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "gfx/pal_spec.hpp"
 
 #include <algorithm>
@@ -20,8 +22,8 @@
 #include <vector>
 
 #include "diagnostics.hpp"
+#include "file.hpp"
 #include "helpers.hpp"
-#include "platform.hpp"
 #include "util.hpp" // UpperMap, parseDigit
 
 #include "gfx/main.hpp"
@@ -174,6 +176,28 @@ void parseInlinePalSpec(char const * const rawArg) {
 	}
 }
 
+void parseEmbeddedPalSpec(Png const &png) {
+	// Generate a palette spec from one palette's length of colors in the embedded palette
+	if (png.palette.empty()) {
+		error("\"-c embedded\" was given, but the PNG does not have an embedded palette");
+		return;
+	}
+
+	// Ignore extraneous colors if they are unused
+	size_t nbColors = png.palette.size();
+	if (nbColors > options.maxOpaqueColors()) {
+		nbColors = options.maxOpaqueColors();
+	}
+
+	// Fill in the palette spec
+	options.palSpec.clear();
+	auto &palette = options.palSpec.emplace_back();
+	assume(nbColors <= palette.size());
+	for (size_t i = 0; i < nbColors; ++i) {
+		palette[i] = png.palette[i];
+	}
+}
+
 // Appends the first line read from `file` to the end of the provided `buffer`.
 // Returns true if a line was read.
 [[nodiscard]]
diff --git a/src/gfx/process.cpp b/src/gfx/process.cpp
index 318445ec..5cee407a 100644
--- a/src/gfx/process.cpp
+++ b/src/gfx/process.cpp
@@ -8,7 +8,6 @@
 #include <inttypes.h>
 #include <ios>
 #include <optional>
-#include <png.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -77,8 +76,8 @@ public:
 };
 
 struct Image {
-	Png png{};
-	ImagePalette colors{};
+	Png png;
+	ImagePalette colors;
 
 	Rgba &pixel(uint32_t x, uint32_t y) { return png.pixels[y * png.width + x]; }
 	Rgba const &pixel(uint32_t x, uint32_t y) const { return png.pixels[y * png.width + x]; }
@@ -127,14 +126,7 @@ struct Image {
 		return {GrayscaleResult::GRAY_OK, std::nullopt};
 	}
 
-	explicit Image(std::string const &path) {
-		File input;
-		if (input.open(path, std::ios_base::in | std::ios_base::binary) == nullptr) {
-			fatal("Failed to open input image (\"%s\"): %s", input.c_str(path), strerror(errno));
-		}
-
-		png = Png(input.c_str(path), *input);
-
+	explicit Image(Png &&png_) : png(std::move(png_)), colors() {
 		// Validate input slice
 		if (options.inputSlice.width == 0 && png.width % 8 != 0) {
 			fatal("Image width (%" PRIu32 " pixels) is not a multiple of 8", png.width);
@@ -332,28 +324,6 @@ struct AttrmapEntry {
 	}
 };
 
-static void generatePalSpec(Image const &image) {
-	// Generate a palette spec from the first few colors in the embedded palette
-	std::vector<Rgba> const &embPal = image.png.palette;
-	if (embPal.empty()) {
-		fatal("\"-c embedded\" was given, but the PNG does not have an embedded palette");
-	}
-
-	// Ignore extraneous colors if they are unused
-	size_t nbColors = embPal.size();
-	if (nbColors > options.maxOpaqueColors()) {
-		nbColors = options.maxOpaqueColors();
-	}
-
-	// Fill in the palette spec
-	options.palSpec.clear();
-	auto &palette = options.palSpec.emplace_back();
-	assume(nbColors <= palette.size());
-	for (size_t i = 0; i < nbColors; ++i) {
-		palette[i] = embPal[i];
-	}
-}
-
 static std::pair<std::vector<size_t>, std::vector<Palette>>
     generatePalettes(std::vector<ColorSet> const &colorSets, Image const &image) {
 	// Run a "pagination" problem solver
@@ -450,7 +420,7 @@ static std::pair<std::vector<size_t>, std::vector<Palette>>
 			if (i + skipFirst >= options.nbColorsPerPal) {
 				error(
 				    "Each palette spec can only contain up to %" PRIu8
-				    " color%s plus the implict transparent color",
+				    " color%s plus the implicit transparent color",
 				    options.nbColorsPerPal - 1,
 				    options.nbColorsPerPal - 1 == 1 ? "" : "s"
 				);
@@ -992,8 +962,6 @@ static void
 }
 
 void processPalettes() {
-	verbosePrint(VERB_CONFIG, "Using libpng %s\n", png_get_libpng_ver(nullptr));
-
 	std::vector<ColorSet> colorSets;
 	std::vector<Palette> palettes;
 	std::tie(std::ignore, palettes) = makePalsAsSpecified(colorSets);
@@ -1001,11 +969,9 @@ void processPalettes() {
 	outputPalettes(palettes);
 }
 
-void process() {
-	verbosePrint(VERB_CONFIG, "Using libpng %s\n", png_get_libpng_ver(nullptr));
-
+void process(Png &&png) {
 	verbosePrint(VERB_NOTICE, "Reading tiles...\n");
-	Image image(options.input); // This also sets `hasTransparentPixels` as a side effect
+	Image image(std::move(png)); // This also sets `hasTransparentPixels` as a side effect
 
 	// LCOV_EXCL_START
 	verboseDo(VERB_INFO, [&]() {
@@ -1195,9 +1161,6 @@ continue_visiting_tiles:;
 		fatal("Image does not contain any colors");
 	}
 
-	if (options.palSpecType == Options::EMBEDDED) {
-		generatePalSpec(image);
-	}
 	auto [mappings, palettes] =
 	    options.palSpecType == Options::NO_SPEC || options.palSpecType == Options::DMG
 	        ? generatePalettes(colorSets, image)
diff --git a/src/gfx/reverse.cpp b/src/gfx/reverse.cpp
index 8a353108..617504e4 100644
--- a/src/gfx/reverse.cpp
+++ b/src/gfx/reverse.cpp
@@ -107,8 +107,6 @@ static void printPalette(std::array<std::optional<Rgba>, 4> const &palette) {
 }
 
 void reverse() {
-	verbosePrint(VERB_CONFIG, "Using libpng %s\n", png_get_libpng_ver(nullptr));
-
 	// Check for weird flag combinations
 
 	if (options.output.empty()) {
@@ -205,6 +203,7 @@ void reverse() {
 	    {grayColors[0], grayColors[1], grayColors[2], grayColors[3]}
 	};
 	// If a palette file or palette spec is used as input, it overrides the default colors.
+	bool grayscale = false;
 	if (!options.palettes.empty()) {
 		File file;
 		if (!file.open(options.palettes, std::ios::in | std::ios::binary)) {
@@ -280,11 +279,15 @@ void reverse() {
 		for (size_t i = 0; i < palettes[0].size(); ++i) {
 			palettes[0][i] = grayColors[options.dmgValue(i)];
 		}
+		grayscale = true;
 	} else if (options.palSpecType == Options::EMBEDDED) {
 		warnx("An embedded palette was requested, but no palette file was specified; ignoring "
 		      "request");
+		grayscale = true;
 	} else if (options.hasExplicitPalSpec()) {
 		palettes = std::move(options.palSpec); // We won't be using it again.
+	} else {
+		grayscale = true;
 	}
 
 	std::optional<std::vector<uint8_t>> attrmap;
@@ -497,10 +500,10 @@ void reverse() {
 	}
 	png_set_write_fn(png, &pngFile, writePng, flushPng);
 
-	int pngColorType = options.palettes.empty() ? PNG_COLOR_TYPE_GRAY
-	                   : palettes.size() == 1   ? PNG_COLOR_TYPE_PALETTE
-	                                            : PNG_COLOR_TYPE_RGB_ALPHA;
-	int pngDepth = options.palettes.empty() ? options.bitDepth : 8;
+	int pngColorType = grayscale              ? PNG_COLOR_TYPE_GRAY
+	                   : palettes.size() == 1 ? PNG_COLOR_TYPE_PALETTE
+	                                          : PNG_COLOR_TYPE_RGB_ALPHA;
+	int pngDepth = grayscale ? options.bitDepth : 8;
 
 	png_set_IHDR(
 	    png,
@@ -531,17 +534,21 @@ void reverse() {
 		png_byte pngTrans[4] = {};
 		int nbPngColors = 0, nbPngTrans = 0;
 		for (auto const &color : palettes[0]) {
-			if (!color.has_value()) {
-				continue;
+			if (color.has_value()) {
+				pngPalette[nbPngColors].red = color->red;
+				pngPalette[nbPngColors].green = color->green;
+				pngPalette[nbPngColors].blue = color->blue;
+				pngTrans[nbPngColors] = color->alpha;
+				if (color->alpha < 255) {
+					nbPngTrans = nbPngColors;
+				}
+			} else {
+				pngPalette[nbPngColors].red = 255;
+				pngPalette[nbPngColors].green = 255;
+				pngPalette[nbPngColors].blue = 255;
+				pngTrans[nbPngColors] = 255;
 			}
-			pngPalette[nbPngColors].red = color->red;
-			pngPalette[nbPngColors].green = color->green;
-			pngPalette[nbPngColors].blue = color->blue;
-			pngTrans[nbPngColors] = color->alpha;
 			++nbPngColors;
-			if (color->alpha < 255) {
-				nbPngTrans = nbPngColors;
-			}
 		}
 		png_set_PLTE(png, pngInfo, pngPalette, nbPngColors);
 		if (nbPngTrans > 0) {
diff --git a/src/link/assign.cpp b/src/link/assign.cpp
index e3c7c47b..0b985ece 100644
--- a/src/link/assign.cpp
+++ b/src/link/assign.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "link/assign.hpp"
 
 #include <algorithm>
@@ -16,7 +18,6 @@
 #include "helpers.hpp"
 #include "itertools.hpp"
 #include "linkdefs.hpp"
-#include "platform.hpp"
 #include "verbosity.hpp"
 
 #include "link/main.hpp"
diff --git a/src/link/object.cpp b/src/link/object.cpp
index 8dfd7387..0ddb97d8 100644
--- a/src/link/object.cpp
+++ b/src/link/object.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "link/object.hpp"
 
 #include <deque>
@@ -18,7 +20,6 @@
 
 #include "helpers.hpp"
 #include "linkdefs.hpp"
-#include "platform.hpp"
 #include "util.hpp" // xfclose
 #include "verbosity.hpp"
 #include "version.hpp"
diff --git a/src/link/output.cpp b/src/link/output.cpp
index 47106466..837e52b2 100644
--- a/src/link/output.cpp
+++ b/src/link/output.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "link/output.hpp"
 
 #include <algorithm>
@@ -19,7 +21,6 @@
 #include "extern/utf8decoder.hpp"
 #include "helpers.hpp"
 #include "linkdefs.hpp"
-#include "platform.hpp"
 #include "util.hpp"
 
 #include "link/main.hpp"
diff --git a/src/link/sdas_obj.cpp b/src/link/sdas_obj.cpp
index 26562bec..65fe12e7 100644
--- a/src/link/sdas_obj.cpp
+++ b/src/link/sdas_obj.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "link/sdas_obj.hpp"
 
 #include <inttypes.h>
@@ -14,7 +16,6 @@
 
 #include "helpers.hpp" // assume, literal_strlen
 #include "linkdefs.hpp"
-#include "platform.hpp"
 #include "util.hpp" // parseWholeNumber
 
 #include "link/fstack.hpp"
diff --git a/src/style.cpp b/src/style.cpp
index 55d15a98..83bd27dc 100644
--- a/src/style.cpp
+++ b/src/style.cpp
@@ -3,14 +3,14 @@
 // This implementation was based on https://github.com/agauniyal/rang/
 // and adapted for RGBDS.
 
+#include "platform.hpp" // isatty, strcasecmp
+
 #include "style.hpp"
 
 #include <stdio.h>
 #include <stdlib.h> // getenv
 #include <string.h>
 
-#include "platform.hpp" // isatty, strcasecmp
-
 #if !STYLE_ANSI
 // clang-format off: maintain `include` order
 	#define WIN32_LEAN_AND_MEAN // Include less from `windows.h`
diff --git a/src/usage.cpp b/src/usage.cpp
index 4bc4849d..9dc95513 100644
--- a/src/usage.cpp
+++ b/src/usage.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "usage.hpp"
 
 #include <stdarg.h>
@@ -8,7 +10,6 @@
 
 #include "diagnostics.hpp" // vfatalx
 #include "helpers.hpp"
-#include "platform.hpp"
 #include "style.hpp"
 #include "util.hpp" // parseWholeNumber
 #include "version.hpp"
diff --git a/src/util.cpp b/src/util.cpp
index 48d73f8a..4a7e6cd5 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include "platform.hpp"
+
 #include "util.hpp"
 
 #include <errno.h>
@@ -9,7 +11,6 @@
 #include <string.h> // strspn
 
 #include "helpers.hpp" // assume
-#include "platform.hpp"
 
 int xfclose(FILE *file) {
 	if (file == stdin || file == stdout || file == stderr) {
diff --git a/test/gfx/alpha_embedded.err b/test/gfx/alpha_embedded.err
deleted file mode 100644
index eb832e43..00000000
--- a/test/gfx/alpha_embedded.err
+++ /dev/null
@@ -1,4 +0,0 @@
-error: Failed to fit tile colors [GB:07,09,05; GB:12,14,05; GB:20,21,06] in specified palettes
-note: The following palette was specified:
-      - [GB:20,21,06; GB:12,14,05]
-Conversion aborted after 1 error
diff --git a/test/gfx/alpha_embedded.out.2bpp b/test/gfx/alpha_embedded.out.2bpp
new file mode 100644
index 00000000..53d788a0
Binary files /dev/null and b/test/gfx/alpha_embedded.out.2bpp differ
diff --git a/test/gfx/alpha_embedded.out.pal b/test/gfx/alpha_embedded.out.pal
new file mode 100644
index 00000000..7067c369
Binary files /dev/null and b/test/gfx/alpha_embedded.out.pal differ
diff --git a/test/gfx/implicit-overflow.err b/test/gfx/implicit-overflow.err
index 7db00eb7..b952b260 100644
--- a/test/gfx/implicit-overflow.err
+++ b/test/gfx/implicit-overflow.err
@@ -1,2 +1,2 @@
-error: Each palette spec can only contain up to 1 color plus the implict transparent color
+error: Each palette spec can only contain up to 1 color plus the implicit transparent color
 Conversion aborted after 1 error
diff --git a/test/gfx/middle_transparent_embedded.err b/test/gfx/middle_transparent_embedded.err
new file mode 100644
index 00000000..a15e6782
--- /dev/null
+++ b/test/gfx/middle_transparent_embedded.err
@@ -0,0 +1,2 @@
+error: Each palette spec can only contain up to 3 colors plus the implicit transparent color
+Conversion aborted after 1 error
diff --git a/test/gfx/middle_transparent_embedded.flags b/test/gfx/middle_transparent_embedded.flags
new file mode 100644
index 00000000..3f89189c
--- /dev/null
+++ b/test/gfx/middle_transparent_embedded.flags
@@ -0,0 +1 @@
+-c embedded
diff --git a/test/gfx/middle_transparent_embedded.png b/test/gfx/middle_transparent_embedded.png
new file mode 100644
index 00000000..8550ee94
Binary files /dev/null and b/test/gfx/middle_transparent_embedded.png differ
diff --git a/test/gfx/middle_transparent_gbc_spec.err b/test/gfx/middle_transparent_gbc_spec.err
new file mode 100644
index 00000000..a15e6782
--- /dev/null
+++ b/test/gfx/middle_transparent_gbc_spec.err
@@ -0,0 +1,2 @@
+error: Each palette spec can only contain up to 3 colors plus the implicit transparent color
+Conversion aborted after 1 error
diff --git a/test/gfx/middle_transparent_gbc_spec.flags b/test/gfx/middle_transparent_gbc_spec.flags
new file mode 100644
index 00000000..ee846ac1
--- /dev/null
+++ b/test/gfx/middle_transparent_gbc_spec.flags
@@ -0,0 +1 @@
+-c gbc:middle_transparent_gbc_spec.pal
diff --git a/test/gfx/middle_transparent_gbc_spec.pal b/test/gfx/middle_transparent_gbc_spec.pal
new file mode 100644
index 00000000..60d295fc
Binary files /dev/null and b/test/gfx/middle_transparent_gbc_spec.pal differ
diff --git a/test/gfx/middle_transparent_gbc_spec.png b/test/gfx/middle_transparent_gbc_spec.png
new file mode 100644
index 00000000..8550ee94
Binary files /dev/null and b/test/gfx/middle_transparent_gbc_spec.png differ
diff --git a/test/gfx/middle_transparent_png_spec.err b/test/gfx/middle_transparent_png_spec.err
new file mode 100644
index 00000000..a15e6782
--- /dev/null
+++ b/test/gfx/middle_transparent_png_spec.err
@@ -0,0 +1,2 @@
+error: Each palette spec can only contain up to 3 colors plus the implicit transparent color
+Conversion aborted after 1 error
diff --git a/test/gfx/middle_transparent_png_spec.flags b/test/gfx/middle_transparent_png_spec.flags
new file mode 100644
index 00000000..bbc4097d
--- /dev/null
+++ b/test/gfx/middle_transparent_png_spec.flags
@@ -0,0 +1 @@
+-c png:middle_transparent_png_spec.pal.png
diff --git a/test/gfx/middle_transparent_png_spec.pal.png b/test/gfx/middle_transparent_png_spec.pal.png
new file mode 100644
index 00000000..0e8829de
Binary files /dev/null and b/test/gfx/middle_transparent_png_spec.pal.png differ
diff --git a/test/gfx/middle_transparent_png_spec.png b/test/gfx/middle_transparent_png_spec.png
new file mode 100644
index 00000000..8550ee94
Binary files /dev/null and b/test/gfx/middle_transparent_png_spec.png differ
diff --git a/test/gfx/reverse_inline_palette.2bpp b/test/gfx/reverse_inline_palette.2bpp
new file mode 100644
index 00000000..a38193d0
--- /dev/null
+++ b/test/gfx/reverse_inline_palette.2bpp
@@ -0,0 +1 @@
+U3U3U3U3U3U3U3U3
\ No newline at end of file
diff --git a/test/gfx/reverse_inline_palette.flags b/test/gfx/reverse_inline_palette.flags
new file mode 100644
index 00000000..75e5e5f1
--- /dev/null
+++ b/test/gfx/reverse_inline_palette.flags
@@ -0,0 +1 @@
+-c #ff0000,#00ff00,#0000ff,#ffffff