If I have a radio group with buttons:

... how can I show only images in the select option i
Here is a simple jQuery UI solution based on the example here:
http://jqueryui.com/button/#radio
Modified code:
jQuery UI Button - Radios
jQueryUI takes care of the image background so you know which button is checked.
Beware: If you want to set a button to checked or unchecked via Javascript, you must call the refresh function:
$('#radio3').prop('checked', true).button("refresh");