I have an IMG tag with a grayscale image. I hooked up a Hover() event in order to change the \"src\" to a color image on hover, and back to grayscale on mouse-out.
You could do this cross fade with css3 using transition too. Not available for all browsers but still... http://www.w3schools.com/css3/css3_transitions.asp
In similar way to CSS: image link, change on hover
For example:
#showForm
{
background: transparent url('images/AddButtonSmallGray.gif') center top no-repeat;
-webkit-transition:all 0.3s ease-in-out;
-moz-transition:all 0.3s ease-in-out;
transition:all 0.3s ease-in-out;
}
#showForm:hover {
background-image: url('images/AddButtonSmall.gif');
}