Photos are a powerful way to communicate on Facebook. Fred Perrotta from Kissmetrics has some fantastic advice on best practices for using images in Facebook advertising:
The most important part of your ad is the image. You can write the most brilliant copy in the world, but if your image doesn’t catch a user’s eye, you won’t get any clicks.
Don’t use low-quality images, generic stock photography, or any images that you don’t have the rights to use. Don’t steal anything from Google Images. Unless you’re a famous brand, don’t use your logo.
Images of people work best. Preferably their faces. Use close-ups of attractive faces that resemble your target audience.
Facebook ad images are small (100 x 72 pixels). Make sure to focus on a person’s face and crop it if necessary. Don’t use a blurry or dark picture.
Advanced tip: Use images of people facing to the right. Users will follow the subject’s line of sight and be more likely to read your ad text.
-Fred Perrotta, A Deep Dive Into Facebook Advertising
Hopefully you now have a better idea of what kind of images work best for Facebook advertisements. Remember to test what people respond to for your own company, and watch your competitors see what’s working for them.