change button image on hover?

[scooter]

thanks for your input...
perhaps i might elabrate,
i can/have found code
i know each button will have a hover event 2 gifs for each button
this is what i found that looks useable
but i'm not sure how to target each of the 3 existing buttons
a#image1
{
display: block;
width: WIDTHHEREpx;
height: HEIGHTHEREpx;
background-image: url(URL TO ORIGINAL IMAGE.gif);
margin: 0 auto;
}
a#image1:hover
{
background-image: url(URL TO MOUSEOVER IMAGE.gif);
}
a .alt
{
display: none;
}