Shadow behind image in Firefox/Safari/Chrome

I am using the following line in my css to put a nice shadow behind an image:

filter:progid:DXImageTransform.Microsoft.Shadow(color=#848A84, Direction=135, Strength=4);

It works great in IE (I am using version 7).  You can see it at http://www.celinevictoria.com/newsite/index.php?act=viewCat&catId=7 .

But the client uses Firefox, and sometimes Google Chrome.  We would like it to also work in these other browsers, as well as Safari, if it is at all possible.

I realise this is a Microsoft feature, and so might only be meant to work in IE, but is there a similar function I can use for other browsers?  Or a different one that would give a similar effect but also work in IE?

I am programming in php.

Thanks,
Christine.