jQuery(document).ready(function($){
	// HOVER
	$("#nav a").hover( 
		// over
		function(){
			var theImg = $(this).find('img:first');
			// store the original image src
			theImg.data( "originalsrc" , theImg.attr("src") );
			
			// add -over to the image unless it is already -over
			if (!theImg.attr("src").match(/-over/) ) {
				theImg.attr( "src", theImg.attr("src").replace(/\./, "-over.") );
			}
			
		},
		
		// out
		function(){
			var theImg = $(this).find('img:first');
			// replace the original src
			theImg.attr("src", theImg.data("originalsrc"));
		}
	);
});