How can I make web picture galleries from pictures matching a keyword search?

I have a bunch of pictures tagged with keywords (currently in iPhoto). I want to have a website where someone can search for a keyword, or choose a keyword from a list, and have a web photo gallery generated of all matching pictures. I have hosting with mySQL and PHP. I am familiar with computers, but I can NOT program this myself, I’m looking for some “easy” way to do it. A blog site or free homepage or such would be fine if they include this functionality, or a pre-made website platform I can install on my host with this functionality. It does not have to be highly customizable or elegant.