Very simple question here: Are ILC_COLOR32 Image Lists alpha-premultiplied or not? Various questions on Stack Overflow, like this one, imply they are; this wxWidgets bug, however, indicates otherwise. The only place where Microsoft actually says ILC_COLOR32 is used for alpha-blended image list entries doesn't say (and all ILC_COLOR32's docs say about it is that it is a "32-bit DIB section", which, if I understand the BITMAPINFOHEADER docs correctly, technically does not contain alpha information; the top 8 bits of each color are ignored). Thanks!
The images that you supply to, and extract from, ILC_COLOR32 image lists do not have pre-multiplied alpha channels.