on hover change image code example

Example 1: how to enlarge image when hover on in css

img:hover {
transform: scale(1.3);
}

Example 2: on hover change img

#Library {
   background-image: url('LibraryTransparent.png');
   height: 70px;
   width: 120px;
}

#Library:hover {
   background-image: url('LibraryHoverTrans.png');
}