CVS Photo are a very large US chain (7,000 branches) providing photo printing services, with online ordering through http://www.cvsphoto.com/home.aspx 

Lovely passage from CVS Photo contract, be careful, your photos are theirs if you use their online photo printing service:

For all Materials you may use or allow others to use in connection with the Service, including Materials posted or submitted to the Service:
* You grant to the Web Site and its service providers and licensees a non-exclusive, royalty-free, perpetual, irrevocable, unrestricted, world-wide right and license to access, use, copy, reproduce, distribute, transmit, display, perform, communicate to the public, modify, adapt, publish, translate, create derivative works from, and otherwise use such Materials (in whole or in part) in connection with the Service, using any form, media or technology now known or later developed, without providing compensation to you or any other person, without any liability to you or any other person, and free from any obligation of confidence or other duties on the part of the Web Site or its service.

http://www.cvsphoto.com/disclaimers/terms.aspx

A quick digging around reveals a lot of other online photo printing services have similar clauses in their contracts. Keep your eyes open people.