If you haven't quit Facebook yet, you'll love free Firefox add-on Facebook PhotoZoom, which magnifies photos as you mouse over them so you don't have to click through albums or profile pictures to view them full-size.
Even disregarding Facebook's lack of speed and reliability when flipping through photo albums, this add-on is super-helpful for seeing full-size pictures in any situation. Not only is it great for browsing through full photo albums, letting you just page through and mouse over photos instead of loading each one separately, but it works anywhere on Facebook, not just photo albums. If you're on a profile page and want to see a larger version of someone else's thumbnail, all you need to do is mouse over it instead of going to their page and viewing the full photo.
As with most things that pop up as you mouse around a page, it can get a little annoying when you just want to browse around. But in those situations where a friend or family member returns from overseas with 50 Facebook photos, enabling this add-on can make your life much easier when trying to check them out.
Facebook PhotoZoom is a free download, works wherever Firefox does.