I did a little experimenting with MHTML last night and found it's
possible to use this technique to embed images in a TiddlyWiki within
IE6. It can be used to complement data: URIs which achieve the same
thing in modern browsers.
http://softwareas.com/embedded-images-in-tiddlywiki-under-ie6-via-mhtml-proof-of-concept
Works, but has a couple of significant problems - (a) I had to
hardcode the location of the tiddlywiki inside the stylesheet as I'm
not sure how to make relative references in MHTML; (b) I could only
get it working with one image for some reason. Both of these could
probably be overcome with further investigation.