encryptdesigns

I've been doing research on the Apache Rewrite Guide but I'm having a little trouble making sense of what I need to do.

Here's my situation:

Server1
Server2
Server3

All have their own sets of images for products.

ServerX has a website setup on it where all the images will be stored to be used on all of the other servers.

So how do I get Server1, 2 and 3 to use all the images on the sub-domain on ServerX. I know how to use the "Alias" command to allow each website on Server1, 2 and 3 to pull from a "specific location" on Server1, 2 or 3, but HOW do I get 123 to use images on ServerX?

Any ideas?