How to make image change depending on theme

[Frost]

Ok I have a new.. weird question...

I want to be able to change my signature divider depending on what theme it's currently switched on.

I have everything done where I can change the image/code/text whatever via my acp and I even got ctracker to hush about using html, and my db to quit whining about an image being inserted into it...

Now the last little problem is how to set the path to the image in the acp

I am using this code right now

<center><img></center>

The only problem with this, is on a dark theme the white divider shows up nice, but on one of my lighter themes with a white post bg, you can't see the image.

Is there a way to make it load the image from the /images directory of whatever theme is being used?

I've tried using { TEMPLATE } and a little bit of relative path.. still no luck

Any ideas?