Custom Forum Legend - Perforum Basis

[ZiNgA BuRgA]

Then you should check the URL that is being put in (right-click -> Copy Image Location in Firefox) and track the issue there.

But I think you've somewhat got the wrong idea.  All you're doing is changing the path of the image.  If you want what the first post is talking about (different images per forum), you'll need separate templates for each forum, with a forum template prefix set up for each forum.
Alternatively, you could use something like this:

HTML Code

<img src="{$theme['imgdir']}/forum{$forum['fid']}/{$lightbulb['folder']}.gif" alt="{$lightbulb['altonoff']}" title="{$lightbulb['altonoff']}" class="ajax_mark_read" id="mark_read_{$forum['fid']}" />

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And have your images in:
images/forum1/on.gif
images/forum1/off.gif
images/forum2/on.gif
etc
...where the numbers refer to the forum ID.  If you do this, you'll need an image for every single forum and don't need XThreads.