Stick this in your footers
<script type='text/javascript'>
/*
Change Any Image On Page
Created by iFusion
*/
var img_b = new Array();
img_b[img_b.length++] = [ "http://www.smfboards.com/Themes/default/images/off.gif" , "http://i71.photobucket.com/albums/i124/king_09/off.gif" ]
img_b[img_b.length++] = [ "http://http://www.smfboards.com/Themes/default/images/on.gif" , "http://i71.photobucket.com/albums/i124/king_09/turtleicon.gif" ]
var all_images = document.getElementsByTagName('IMG');
for(i=0;i<all_images.length;i++){
for(j=0;j<img_b.length;j++){
if(all_images[i].src == img_b[j][0]){
all_images[i].src = img_b[j][1];
}}}
</script>