Here's a starting point for you. I haven't tested this but something like this should work.
Find this block from your link_summary.tpl (this can vary depending on what template you're using.)
Code:
{if $link_category neq ""}
<span id="ls_category-{$link_shakebox_index}"><b><a href="{$category_url}" style='text-decoration:none;'>{#PLIGG_MiscWords_Category#}</a></b>: <a href="{$category_url}">{$link_category}</a></span>
{/if} That block shows the category of the story and I think you can show the proper icons by modifying that code a bit.
I mean something like this
Code:
{if $link_category eq "arsenal"}
<img src="path-to-image/arsenal.png" />
{elseif $link_category eq "liverpool"}
<img src="path-to-image/liverpool.png" />
{/if} Ok. As I said haven't tested it and I'm not sure if you need to use category id's instead category names. And maybe you need to add something more to the clause but there's a starting point. If this doesn't work let me know and I'll try to figure it out.