Thanks tbworld.
So you're right, adblock does find the div ID ad_thread_first_post_content and hides it dynamically.
However, if I was able to rename that ID to another one that did not include the word "ad" in it, then this would not be blocked (I have tested this theory with changing the ID in firebug).
So what I am trying to do now is make it so that I can change that ID permanently (versus just temporarily editing it with firebug). I am not sure what I need to do to make this happen.
Once I have the div renamed, I will then be able to have an alternate image show up in place of the ad that adblocker blocks.
Hope that makes sense...
Thank you.