var popup = "Sorry, this image is copy-protected.";

function noRightClick() {
	alert( popup );
	return false;
}

function disableImages() {
	if ( document.getElementsByTagName ) {
		var imgs = document.getElementsByTagName( "img" );
		for ( var i=0; i<imgs.length ; i++ ) {
			imgs[i].oncontextmenu = noRightClick;
		}
	}
}

addLoadEvent(function() { disableImages() });