I had a lot of fun searching the tag "cat" - I found this in the creative commons by Zumi, owner of Malingering - TheDamnMushroom
Go visit Cats in Space.
I think Flickr is a good tool - we use it at the library and often post children's events and other interesting things.
As a personal account...I haven't used it. I tend to store my photos at http://www.ofoto.com/ and share them from there. I'm not too socially open on photo sharing.
5). The Flickr fun stuff....I could definately see our library using the movie poster and badge maker. Actually a lot of the tools could come in handy. I think I'll be trying them out for one of my next fun posters for an event/program. The Big Huge Labs and Image Chef are fantastic....ToonDoo I tried out but I'd get myself into trouble making stuff with that. :o) It'd be too easy to be sarcastic or some such.
6). Online Image Generators - I think these would be a lot of fun to put together to host a tweens/teens computer class or program. Legality issues are huge and often muddy when it comes to library priveleges. (For example - A librarian can read a book for a storytime audience but it can't be recorded and played back on a podcast without getting into deep waters.) I've heard conversation where Disney (do I need the copyright symbol after THAT now?) went after libraries that had used images to promote books/etc. Sticky wicket!
And just for fun ---- check out http://www.youtube.com/watch?v=pyLTqBARFt8 . This made me laugh so hard!