Inserting HTML manually

Hi, I have all my users pics saved in the same directory, with a list of each users pics in a DB. So, I want to make my own "insert images" interface. Then when I got the HTML, I would like to insert it into the FCKeditor. I hope you understand what I mean, I'm sort of looking for a simple function like FCK.EditorWindow.insertHTML("<img src='a.gif'>");

Thanks!