I love We Heart It, which lets you collect pictures anywhere easily, with a button you can drag to your favorites/button bar. There's also the ability to right-click on a picture and see "Save image on my Heart," but I don't know if that's a Firefox extension or not; I can't remember.

[ETA: I did remember! Go to the site. You see a pink button with "Add +" on it in white text on the upper right part of the screen, looking rather like this: .

Now, if you hold down and drag said button to the bookmarks/buttons bar, you can get that to stay there. If, however, you just click on it, it takes you to a page that offers you the ability to download; doings so installs the FireFox extension!]

I'm fireandarose there, so I can be found at http://weheartit.com/fireandarose.

Anyone there want to friend me/have me friend them? Want to join up if you don't have an account? I find it very useful way to save images without using massive hard drive space or having to download and upload again to, like, PhotoBucket.