The corresponding Facebook app is also available now.

It is available at:
http://apps.facebook.com/phreetings/

in Opera, it appears it only displays the thumbnail results after ALL thumbnail results have been loaded into cache, not as they are streaming in. So give it a few seconds and you will see the results on the left side. Then you can drag and drop a selected photo to the top box, type your greeting, and then click send.

http://phreetings.com/

phreetings = photo + greetings

a place to create e-greetings using Creative Commons photos by drag and drop

http://picturesandbox.com

searches Creative Commons photos on Flickr, plus adds other collections like SmugMug and Webshots; and adds microstock sites like StockXpert, Dreamstime, Fotolia, and LuckyOliver for purchasable images.

And it is designed to calculate your screen real estate so it can fill up your screen with as many thumbnail results as possible

see 1,500 thumbnails up on quadscreens here:
http://picturesandbox.com/quadscreens.html