PicLens is a great way to visualize the results from Google Image Search as a never-ending list of thumbnails. Once you find an interesting photo, you can double-click on it and view it in full-screen. PicLens can also create slideshows from Google Image Search's results so you can enjoy Dali's paintings or Google's doodles.
For Picasa Web Albums, the slideshow doesn't include captions or file names, but it lets you navigate inside an album. The slideshow also works for Picasa Web's search results and it shows the images in full-screen.