I have always had the same problem, someone clicks on my flickr picture, and they access everything in my "open to the public" folder. My solution: I have created a flickr account that is only ebay and C/L pictures. So if someone wants to see everything I have for sale, great. Flickr lets you open as many free accounts as you would like, as far as I know. I have several accounts, and have not run against a limit yet.