<!DOCTYPE HTML>
<html reftest-zoom="0.8">
<head>
<style>
div { margin:1em; }
/* A 7x7px image, black with a 5x5 transparent box centered in it */
div.box { background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAcAAAAHCAYAAADEUlfTAAAAFklEQVQImWNgYGD4jwdDCCxgQCWxYgBX8hfpeym4dwAAAABJRU5ErkJggg==); }
/* A 7x5px image, black with a 5x5 transparent box centered in it */
div.vstrip { background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAcAAAAFCAYAAACJmvbYAAAAFElEQVQImWNgYGD4z4Ad/GcYAEkAw+kJ94z5rSYAAAAASUVORK5CYII=); }
/* A 5x7px image, black with a 5x5 transparent box centered in it */
div.hstrip { background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAHCAYAAADAp4fuAAAAE0lEQVQImWNgYGD4jwXTD2DYDgDN4Qn3yMcPlwAAAABJRU5ErkJggg==); }
</style>
</head>
<body>
<div class="box" style="background-position:-1px -1px; width:5px; height:5px;"></div>
<div class="vstrip" style="background-position:-1px 0px; width:5px; height:22px;"></div>
<div class="hstrip" style="background-position:0px -1px; width:22px; height:5px;"></div>
</body>
</html>