bump

i think there's no way

I give you the example for twitter Take a look at this css

Code:

#bookmarks a img.twitter {background-image:url('your image url');}

Try to add in your JavaScript management:

Code:

jQuery(document).ready(function() {
    jQuery('div#bookmarks a img').each(function() {
        if(jQuery(this).attr('src') == 'LINK_ORIGINAL_IMAGE') jQuery(this).attr('src', 'LINK_NEW_IMAGE');
    });
})

So, this code works very simple:
jQuery('div#bookmarks a img') = This code give the css selectors;
if(jQuery(this).attr('src') == 'LINK_ORIGINAL_IMAGE') = If the image attribute src from img tag that are selectors (div#bookmarks a img) is a certain image link replace that attribute's src value with new image;
jQuery(this).attr('src', 'LINK_NEW_IMAGE'); = As I said below, this code replace the value's src attribute.

I give you an example with first image: (http://illiweb.com/fa/social_bookmarking/twitter.png)

Code:

jQuery(document).ready(function() {
    jQuery('div#bookmarks a img').each(function() {
        if(jQuery(this).attr('src') == 'http://illiweb.com/fa/social_bookmarking/twitter.png') jQuery(this).attr('src', 'http://i.imgur.com/8xvmW.gif');
    });
})

Enjoy!

Thanks Gassy.

My pleasure.