Cover your assets, and theirs.
What if someone else were making money using a picture you snapped and you weren't profiting from it? What if someone used a photo of you in a questionable manner?
Take a close look at your own Web site.
Are you sure that all the rights for each and every one of those images has been cleared and been paid for?
If not, and you haven't been sued, consider yourself lucky. Then contact a RightsAssist representative, who can start you down the path to proper content licensing.