After playing with Flickr for awhile, I chose to use http://bighugelabs.com/flickr/mosaic.php, the Mosaic Maker. My search was New York City Skies. I found some pretty cool pictures.
My thoughts on using this in the library is to create poster to do a booktalk on. Not something that will give away a lot of information, but just a few clues as to what is going to happen.
This site is also something that I would like to use for myself.