The CSS3 box-shadow property is a new way of adding drop shadow effects just by editing a style sheet. There’s no need to use Photoshop! Just open your style sheet in a text editor and away you go. Well, it’s almost as simple as that but not quite. There’s one caveat and that is browser support. The box-shadow property is supported by Firefox and Safari (and Google Chrome), using the proprietary -moz- and -webkit- prefixes, but it’s not supported by Internet Explorer (or other browsers). For this reason, I think the box-shadow property is ideal for adding image link hover effects where the shadow is not absolutely essential but where it provides a nice style enhancement (enrichment) for modern browsers…
Direct link: CSS3 box-shadow and Image Hover Effects