I'm going into Facebook advertising and you're required to have an image with each ad. It's obviously important with good images to get people's attention.

On that note, I was wondering if anyone knows some good ways to get effective images for facebook ads? I'm thinking of outsourcing gigs, software that helps, or image collections. I can foresee that I'd need a lot of different images to test.

I'm in the health/beauty market btw, so I imagine that headshots of attractive women/men would work well.

Any tips would be appreciated on where to get lots of good images, preferably pre-formatted to the right dimensions.