How can I Resize & Enlarge an Image (like sprite icons) via CSS 3? - resize

Question

Dear folks.
Imagine a sprite image called icons.png assigned to css class .icons with various 10x10px graphs. Now you want another class which scales up the sprite graphics exactly twice 200% (making them 20x20 pixels on the screen)
How do I achieve this enlargement purely in CSS?
Much appreciated!
.icons, .iconsbig{ /* WORKS FINE */
background-image:url(http://site.org/icons.png);
background-repeat:no-repeat;
vertical-align: middle;
display: block;
height:10px;
}
.iconsbig{ /* make this one twice as big as the original sprite */
background-repeat:no-repeat;
height:20px;
background-size: 20px auto;
image-rendering:-moz-crisp-edges;
-ms-interpolation-mode:nearest-neighbor;
}
update:
problems with the above code:
It works in IE9, but not in FireFox, by most used browser doesnt know how to resize????
in IE9, the enlargement is smudgy and not neithrest neighbour pixel perfect at all??

Answer 1

It is supported in pretty much everything except for < IE9...
.iconsbig {
-moz-background-size: 20px;
background-size: 20px;
image-rendering:-moz-crisp-edges;
-ms-interpolation-mode:nearest-neighbor;
}
W3C spec.
Update
Looks like Firefox wants its vendor prefix (-moz) on the property.

Answer 2

You can use the css3 background-size property:
.iconsbig {
background-image:url(http://site.org/icons.png);
background-size: 20px 20px;
}