At the beginning of your html scripting add the "No right click" script. This means when a person goes to right click on your image they will receive a warning that this feature is not available on this page. If you have many pages with images then you will need to do this on every one of your web pages.

<script language=JavaScript>
<!--

//Disable right mouse click Script

var message="Function Disabled!";

///////////////////////////////////
function clickIE4(){
if (event.button==2){
alert(message);
return false;
}
}

function clickNS4(e){
if (document.layers||document.getElementById&&!document.all){
if (e.which==2||e.which==3){
alert(message);
return false;
}
}
}

if (document.layers){
document.captureEvents(Event.MOUSEDOWN);
document.onmousedown=clickNS4;
}
else if (document.all&&!document.getElementById){
document.onmousedown=clickIE4;
}

document.oncontextmenu=new Function("alert(message);return false")

// -->
</script>