I'm not sure if this is a security hole or just a weird bug, but the options table in my zenphoto database is growing rapidly due to duplicate entries - for example there are hundreds of entries of "thumb_size". It's getting hundreds of new entries per minute and affecting the display of the website since the website queries are finding the new, incorrect database values instead of the ones I set.
Edit: It was a database issue which I resolved thanks to a helpful tooltip from zenphoto