at the bottom of the page where you are writing to post there is a box that says attatch file: and next to it a box that says browse. click breowse and look in your pics folder and then click on that. or if you know the directory and file name you can manually enter it (dos anyone?) and your pics should come up.
it sounds to me that the person you bought the tank from might have also gotten it used and couldn't figure out how to deal with the holes drilled in the bottom. these were most likely first drilled to make use of a standpipe setup. if you would like to set up a safer and more stable filtration system, you can do some searches in the database for standpipes and sumps to get an idea of how they work. it wouldnt be a cheap project, but it would definately make your system much more stable, and would allow you to keep a much larger variety of live in the tank healthy and happy.