Lately, I'm seeing a large number of image hosting sites for sale on DigitalPoint forum and SitePoint forum. Most of the owners use Adsense above and/or below the images.

I just want to know is it okay to have Adsense on image hosting sites?
(assuming the owner does not own the image)

Adsense policy on copyright material -
Copyrighted Material
AdSense publishers may not display Google ads on webpages with content protected by copyright law unless they have the necessary legal rights to display that content.
One of the points mentioned under content guidelines -
Any other content that is illegal, promotes illegal activity or infringes on the legal rights of others