Does the prohibition of images, especially those of animate beings, apply only to hanging them on walls, or does it also include placing them on the internet, and why are they found on some Islamic websites?

It is permissible, according to the majority of scholars, to photograph that which does not possess a soul. As for photographing living beings, if it is photographic (i.e., not a sculpted image) and does not involve any religiously prohibited elements, then there is a difference of opinion among contemporary scholars regarding its permissibility, with some holding it to be permissible. However, three-dimensional sculpting or hand-drawn images are forbidden.