Stephen,
We could even convert all bitmaps to little-endian, since only Mac uses big-endian and we know that nobody important uses Macs.
Shouldn't we support both endians?
We do. Or how else would the system work?! The issue is not about _bitmaps_ (those are fine whatever platform you're on) but about the interpretation of what _pixels_ are where in any given Form. So it's about forms not bitmaps.
If an image opens with big-endian bitmaps on a little endian machines, couldn't we automatically correct them on startup? Sure it will take time, but if startup time is important, just save your image and the bitmaps get saved in the native endianness. I suppose you might need a class for each endianness (LittleEndianBitmap, BigEndianBitmap).
Again, this issue is not about bitmaps. It's about forms which do already include information about their 'supposed' endianness. And yes you could do what you're describing (and even do so in a pretty fast way if you look at Form>>unhibernate). It just needs to be figured out if it's worth the effort or not.
Cheers, - Andreas