Why do gallery sites make a separate page for each image?

Question

User interface

Here I look at sites where collections of images are collected and I see the same behavior incomprehensible to me:
There is a page with a list of images - small previews. When I click on the preview, it redirects me to a page that contains this picture in an incomplete size and sometimes some little useful information. And only from this page I can save the image.
Actually the question is: why are they shoving this intermediate page everywhere? There is no benefit from it, and for the user it is an extra step to save the image.
The only thought that comes to my mind is that this is done to increase the number of hits. To get more money for advertising. Maybe I'm wrong and there is some kind of sacred meaning in this? Why not make the preview in the list a direct link?

Answer 1

Most likely this is a feature of the engine that they use.
+ Each photo can be commented on.
It could have been done better, but why, when the owner no;%:?: