Saving a version 7 .ai expands raster effects into images and flattens
images with see-through pixels, opacity or a blending mode, and both
draw the art with the renderer. An image the renderer couldn't decode
drew nothing, so it was missing from the result, and the reply carried
no note. A semi-transparent image cut short was removed without one.
The save now compares decode_failures() before and after it writes the
artboards, as Expand Appearance and the raster exports do, and adds
"an image couldn't be decoded and is missing from the picture" to its
warnings once.
Docs: docs/mcp.md (aiVersion "7").