obrazki = new Array();

function b_on(img){
	eval("source = document.images."+img+".src");
	ext = source.substr(source.length-4,4);
	name = source.substr(0,source.length-4);
	eval("document.images."+img+".src = '"+name+"b"+ext+"'");
	}

function b_off(img){
	eval("source = document.images."+img+".src");
	ext = source.substr(source.length-4,4);
	name = source.substr(0,source.length-5);
	eval("document.images."+img+".src = '"+name+ext+"'");
	}

function b_preload(img){
	obrazki[img]=new Image();
	eval("source = document.images."+img+".src");
	ext = source.substr(source.length-4,4);
	name = source.substr(0,source.length-4);
	obrazki[img].src = name+"b"+ext;
	}