Well imho I think this would be very complicated.. how do you make the difference if a user "viewed" the image or "downloaded" it?
There are some sites like deviantart.com that have a download link.. but actually as a user, i never used it. When i want a picture, I use my right mouse button and do a "Save as"...
2. i think it would be wasting ressources anyhow.. because you would need an extra table to store all views(!) by users... for sites that have several hundred thousand of picviews by month.. that would meen tables with millions of entries a year.
PS. if such a feature was implemented, I would certainly turn it off!