Very nice.
Automatically detects images on the same page
Would it be possible to restrict this to just a given tiddler for example? I appreciate this is basically a feature request!
On a minor note that, you seem to be using Markdown syntax for your readme file but your readme has the type text/vnd.tiddlywiki (so it should use TiddlyWiki Wikitext). This is also the case for your Advanced Search plugin FWIW.