This may be completely old news, but I just stumbled across retrievr.
[wikilike_img src=http://static.flickr.com/40/82093731_9f93d80e8f_o_d.jpg|caption=|width=210|align=thumb tcenter]
[wikilike_img src=http://static.flickr.com/37/82093713_82614e7d24_o_d.jpg|caption=|width=400|align=thumb tcenter]
Sketch a bit, and then search for Flickr images that “look” like your sketch.
Via kottke.org via MetaFilter
Technorati Tags: flickr