Good for light background width is 144 px, height is 44 px, copy and paste the code below :
<a href="http://www.a-revolt.org" target="_blank"><img src="http://www.a-revolt.org/images/link_to_a-revolt/a-revolt_org_link_1.png" width="150" height="44" border="0"></a>
 
more will come ...