Look at that, Henry's taking his first steps! Look to your left and your right before crossing the street! Look up at the sky, it's Superman! Look up to your right, there's a green bird at the very top of that tree! In all of these sentences, "look [x]" is being used to mean "look in the direction specified." This is the literal meaning of the ...
When using looks (meaning appearance), I would stick to that definition (different from look): plural noun a person's physical appearance a young woman with wholesome good looks I never chose people just because of their looks. She had lost her looks. Normally looks is only used with people. Otherwise, I would use appearance: The restaurant dish must deliver on both taste and appearance. You ...
You look at something for more details of it; you look on something to see what is going to happen with it, and may overlook its details. After looking at it, you decided to look on for a while.
Writing "look at these pictures" suggests that the reader does not necessarily know which pictures to look at, or perhaps hasn't even noticed the pictures yet. Writing "look at the pictures" assumes that the reader has already seen the pictures and already knows exactly which pictures the writer must be referring to.
determiners - "Look at the pictures" or "Look at these pictures ...
Look back at the picture before you answer the question. To see the answer, look back on the screen. For me, I think it's good to look back to the past.