Make a Potrait out of a Twitter user's followers (profile pics)

I would like to make a portrait of a Photograph, made up of tiny reproductions of photos of the followers of that person on Twitter. I have seen these kind of images made up from photos, I would like to make one from Twitter users. This will require knowledge of the technique as well as a method for cumulating thousands of profile photos from a twitter user. If I like the out come I will ask for several such portraits.