loupe is a lightweight (~1k minified) onhover image magnifier for jQuery. just download jquery.loupe.min.js and initialize it like:
$('selector').loupe({
width: 400, // width of magnifier
height: 300, // height of magnifier
loupe: 'loupe' // css class for magnifier
});
the selector should reference links containing thumbnail images, or images shrunk by the browser. the settings (width, etc.) are optional. some demos:
$('#demo-2').loupe();