make it a requirement..
For those people that post ads in the "For Sale" section, it should be a requirement to post pictures with that ad also. I don't think a single person here would buy something without looking at the pictures. On top of that, we end up begging for and most times finally getting pictures anyways.
If you post an ad in the "For Sale" section, you should post pictures as well. I don't think that'* too much to ask.