This API is very disappointing, and although it's nice to have things officially documented, it's actually nothing new - the RSS feeds on web album pages have been serving up data in this form for a long while.

When will we get the full API that allows us to do useful things with the photos in Picasa Web Albums? For example we urgently need API calls that return the following: - a search function, that can search over all the (community) photos - ways to order the search to return the most recent updates - return all the EXIF data for a photo - find the favorites for a particular user - find the linked galleries for a user