I have been interested in Google AJAX Feed API because, well, this site is about feeds and Google Code has taught me a thing or two.
The Google Gadget supports any direct feed that uses the MediaRSS extensions. In addition, it has configuration support for discovery of public Picasa Web Albums and tag-based search over PhotoBucket. We will most likely add other tag-based domains in the near future. Why not try to work it out with Flickr?
I read about this here; Google AJAX Search API Blog: Slide Show Control now available as a Google Gadget