When you chose to show large images, the very biggest can fit into your browser window. If you open up a slideshow or full-screen view, that can fill your entire monitor. But the thing is that can be a cause for interrupt browsing and user not able to get smoother photo browsing experience. Of course Picasa can use smaller images to make the Internet faster , so Picasa team went deep into the code and gave it a thorough tune-up, and they just make their code smarter.
Now Picasa user can browse large images or fullscreen mode much batter then before. Of Course large images are important, because seeing a photo's little details can make a big difference in photo browsing experience, and result of that now picasa web albums handle large images much faster and batter.
Give full-screen mode a try to see even bigger photos. If you've got a reasonable connection to the Internet, you should be able to hold down one of the arrow keys and zip through the entire album at a pretty good clip, flip-book style. Of course, while you could zoom past entire albums at ludicrous speedbrowsing photos is significantly faster