You should take this a few steps further, and try to destroy all functionaltiy
Disable the microsoft image toolbar, anywhere in your head include template.
Code:
<meta http-equiv="imagetoolbar" content="no">
Disable the right click in Mozilla as well, in your head include (this also works for IE)
Code:
<body oncontextmenu="return false">
Disable copy and pasting in your headinclude put:
Code:
<body ondragstart="return false" onselectstart="return false">