G doesn't consider flash files as part of "image search." You'll see swf files float in and out the SERPs, but it's incredibly rare to see them ranking well. It's generally "site:" searches that reveal them.
The listings will show text snippets from the file itself but (as regularly pointed out here) you just can't depend on any search engine to get real meaning from a flash file.
As far as animated gifs (and any bitmap graphic file) I predict it's only a matter of time before G uses the same OCR technology it developed for Google Catalogs and applies it to web graphics. But that's just conjecture. :)