Originally Posted by Volta
Google doesn't make that easy to do, as best as I can tell you've got to open each page in your browser, right click and select "open image in new tab", and extract the correct URL from the address bar for the new tab. Way too much work IMO, so I'd recommend hosting your images elsewhere. Smugmug & Photobucket both seem to work well here.
On.mobile browsers that is the only way I have found to use Picassa, however from a desktop browser it provides several choices for imbedding an image. Overall I've been pleased with the free picture hosting service.