[idbfs]

Two female image processing researchers recently used a picture of Fabio as a test image in a paper of theirs:

http://arxiv.org/abs/1202.6429

(Additional discussion at http://www.kitware.com/blog/home/post/246)

Personally, I'm all for the use of amusing (arousing?) test images, as long as they exhibit features that actually make for a good test image (a mix of flat and textured regions, sharp boundaries, etc.).