1. A leery anonymous person who replies to your personal ad for the sole purpose of collecting your pics to inflate his or her poor ego. An encounter with a pic collector is always short and obnoxiously one-sided.
2. A one-liner with no identity or personality. Can't carry a conversation. Trades you pics that aren't even his, then cuts you off not because you're unappealing, but because he really has nothing to offer, not even common courtesy.
3. Closet-case paranoid voyeur. Can't handle rejection. Hides behind the Internet like a troll. Hardly gets laid but will collect your pics before rejecting you.
Me: Hey. Hot pic!
Him: Got face pics? Chest pics?
Me: Here you go. Yours?
Him: Have more pics? X pics? Wanna see your ass.
Me: Pic collector? Pic 4 pic!
Him: *sends you moar fake pics*
Me: Ok sent mine.
Him: *dissipates like a nasty fart*