External Links get small arrow gif image

[NeuroLancer]

Hi folks. I've had an idea that I tried to make myself but it went haywire so after a few hours I gave up.

My idea is not original, you see it around at various forums from time to time, but it would be a neat thing to have.

Basically when an external link gets posted a small arrow image gets appended to the end.

like this:

www.test.com/notarealurl

At this time of night I would even settle for the image on ANY link, not just externals Ive been trying to make it work and had some success but every time the posts containing the link gets edited or altered in any way one more appends to the end

I would love to see this made into a small mod. If someone could help that would be simply fantastic.