Hrm I think I know this, but my memory is "elusive" on this part.
If this plane is set in the camera attributes you can set the "thingy" in the attributes to "none". ![Biggrin user added image](images2/smilies/biggrin.png)
Else if the image is on a plane, you can hide the object or go into the attribute editor for the object in question and set render attribute; "Visible" unchecked.
Maybe somebody else can verify this also.
I do not support Bush! Nor Saddam! Long live UN!