This is a very cool visual dictionary. Type in a word and it combines wiktionary content with Flickr images. You can set it to pull from Google and Yahoo images, too, but the richest images are from Flickr. Very interesting to see images for the more intangible nouns such as love and hope. This could be a great tool useful for building a vocabulary wiki for a class.
Just a word of caution. I tried the word "anger" and ended up with a topless woman from Flickr. Granted, the photo was done very artistically, but the images are more definitely NOT censored.