What does it mean if a guy sends you a shirtless picture of himself?

He just wants you for two reasons:

1. To boost his own ego. He wants you to say "you look sexy!" or something along those lines because he's vain.
2. To get into your knickers.

Seriously, a topless picture is in no way romantic, athletic body or not. It is a pathetic attempt at wiggling his way into your underwear.

Demand romance, love, spoiling and attention from boys. Pictures of body parts does not guarantee he'll be a decent or even trustworthy lover.