When advertising using faces will attract more attention.
The face needs to be looking at what you want the prospect to see, be the headline, product etc.
The brain will be drawn to the face and then subconsciously will be drawn to what the eyes of the image appear to be looking at.
Gender matters if you are selling to men. Female customers are usually unaffected by the gender in a photo. But they love babies.
Sexy images make men more impulsive and interested in immediate gratification