Check out this great new tool from Google: Google Image Swirl.

Basically what it does is allows you to dial in images based on how close they are to the last image you selected.  For instance, you can search for cats and keep selecting cats until you find the exact one you’re looking for.  They take image properties into account, such as color and face composition.  I could be crazy, but it also looked like it was pulling out expressions.  Here’s an image of my experiment with cats:

Zac Johnson did a great writeup on how this is relevant to you and your Facebook ad campaigns.  I think it’s also relevant to the many other ad platforms as well.