Extract features from pictures


I’m new to computer vision.
I want to develop a tiny programm,
to find the best picture in a bunch of similar pictures.

Therefore I need some algorithm to extract feature data from
pictures and objects, which I then can compare further.

At each step there should be two pictures in comparison.
Based on the selection (one positiv/one negative) there should
be a recommendation possible for the next iterative step.

Thanks for helping.

How do you define best?

Like in a bunch of cars, the most appealing one.