I have a suggestion. When you download files. You can put a delay.
For example. For unregistered members i have a delay of 30 seconds.
But the delay only works for files not for photos.
Users should have to wait 30 seconds to view an image.
I want to force my users to wait 30 seconds and then they should have to press a button "view download" (view image)
Because viewing an image is also a download. It should not be just for files.
This is my suggestion