diff --git a/src/gfx/process.cpp b/src/gfx/process.cpp
index 630facc46..734af628f 100644
--- a/src/gfx/process.cpp
+++ b/src/gfx/process.cpp
@@ -547,6 +547,7 @@ static void generatePalSpec(Png const &png) {
 	}
 
 	// Fill in the palette spec
+	options.palSpec.clear();
 	options.palSpec.emplace_back(); // A single palette, with `#00000000`s (transparent)
 	assume(options.palSpec.size() == 1);
 	if (embPalSize > options.maxOpaqueColors()) { // Ignore extraneous colors if they are unused
diff --git a/test/gfx/multiple_manual_pals.flags b/test/gfx/multiple_manual_pals.flags
new file mode 100644
index 000000000..17350be21
--- /dev/null
+++ b/test/gfx/multiple_manual_pals.flags
@@ -0,0 +1 @@
+-c #0094ff,#000,#fff,#0021ff -c embedded
diff --git a/test/gfx/multiple_manual_pals.png b/test/gfx/multiple_manual_pals.png
new file mode 100644
index 000000000..51a7a96a6
Binary files /dev/null and b/test/gfx/multiple_manual_pals.png differ