You're asking for something that requires quite a bit of custom logic and will slow the site down considerably. Hopefully, the implementation of threaded view, when it comes, will allow you to spot that kind of diversion and skip it quickly.
I don't care either way, but I have a related question. I've tried to upload smilies a couple of times, small animated GIFs. And they break, i.e. they aren't animated anymore once they are uploaded.
At first I thought Danno's GIFs were hosted elsewhere, but I checked one and it's uploaded here.
How can this be? A GIF is a GIF.
Proof...
[ADDED]
And now I see another thing. Transparancy is gone in the embedded image, but not in the thumbnail.
It's not important. I'm mainly curious why this only happens to some GIFs.
You used the image icon since the image was already uploaded. So, upload it but don't click on the icon that inserts it into the post, but instead find its URL on this server and embed it with the image icon.
Odd thing. I tried the same method to use one of the GIFs in another thread, i.e. used the URL from here. It didn't work. No image at all. The plot thickens.
Either the original uploaded image has been deleted or the url you used is broken/incorrect.
For the BBcode img tag to display the image you need the url of the image after it has been uploaded, not the url that is displayed in the Markdown code that is inserted into a post when you click the up-arrow in the post editor to upload an image.
In my earlier post I used the url of your uploaded blob gif to display your gif animating in my post.