Earns you more money from all your existing site photos.

The Brands 2.0 plug-in for WordPress enables you to earn money from your site's existing photos. It is an advertising engine designed to put brand logos into the corners of your photos. No extra page space is needed; easy installation; and you have full control.

Some features:

Control which photos may be sponsored by advertisers.
Control which advertisers may run their logos on your photos.
Receive electronic payments directly to your PayPal account.
Advantages:

Earn additional money from all your existing photos on your site.
You don't have to hand-over any of your prime real-estate as with other more obtrusive advertising engines.
Just post your editorial content as usual. Brands 2.0 does the rest.
One-time installation.

http://wordpress.org/extend/plugins/brands-20/