A lot of people go and post to  as many images as they can in the hopes that the person will reciprocate and view their gallery and post comments, thus generating views and comments on their own pictures.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi