Oh, man. I could populate the pages of a large book with all the cock shots that have come through my e-mail inbox over the years of working as a fetish model. Slightly less irritating but still cringeworthy is a picture of some dude's headless, bodiless abs, butt, or other anatomy.
Come on guys, lets see your face.
Barring that, send homemade porn. If you're gonna go that way, go all out.