It may be useful for you to know that on the DGM2 affiliate network, they provide data files of the catalogues of many of their affiliates in CSV format. This generally also includes image URLs.

An affiliate network would probably be an easy way of generating revenue anyway, so its probably worth looking into. You may find other networks offer the same.

This site of mine is almost entirely generated using the data files mentioned above:
http://www.allthegadgets.com/