Tor wrote: > [filesystem within a file] It's a nice idea in theory, but makes it quite hard to write a parser for. MS Word files (until recently) were basically FAT filesystems, which makes it easy to handle under Windows but harder to parse when you don't have a convenient DLL to do it lying around. The FlashPix format (now little used?) is also a FAT filesystem; it was this fact that persuaded me that writing a Gimp FlashPix loader wouldn't be particularly easy. So sure, consider the idea, but bear in mind it might be hard to pull off. When this discussion started, I didn't like the idea of XML with binary data portions. I liked the current binary, tagged, format we have, and thought that it should just be extended. However, after the recent discussion I've come around to quite liking an ar-style archive with a XML catalog, XML metadata, and texels as separate members. I think this is roughly what Leonard was suggesting; we should listen to the voice of experience. Austin