If you spend a lot of time gathering and updating your casino review content, BetSource is worth checking out. BetSource is a free service that currently provides marketing materials for nearly 90 casinos across 16 affiliate programs, with more on the way.
The site was created by Garth Wilby, who has been in the industry since 2003 and worked on both sides of the aisle (an affiliate manager from 2003-2006 and an affiliate from 2006 onward). He started the site as an internal resource for his designers, but decided to open it up for others in order to give back to the community.
The resources available include detailed site screenshots, game screenshots, casino fact sheets (including stuff like software used, year established, deposit options, currencies, languages and other info), reviews for individual games, banners for the casinos, and a section of gambling related clip art.
The resources are all free. All Garth asks in return is a link to BetSource so that other affiliates can find the site too. He's also included an interface for contributing new materials so that we can pool our efforts.
For now the site is focused on casinos, but as it expands he'll be adding other verticals. I'd recommend checking it out:
BetSource.com.