Hosting images off-site - would a subdomain cause probs w/Goog?

[Moth]

We're looking to make a big change across all of our client sites and I'd rather learn as much as I can about possible repercussions before we make a change that might result in undesirable results. So, please share your thoughts on what we are considering?

We'd like to move all website images to a subdomain to lighten server load on the main domain...so, all website images would be at a designated subdomain for the client, like: images.clientdomain.com . Or, we could host all clients images at one main imagesdomain.com . We're talking quite a bit of resource $ here... a lot of images and it's only going to grow and consume a bigger portion of our server and bandwidth resources. The server process load is the main concern for considering this change. Moving everyone's images to a different server would really help us.

My concerns are:
a) Sites may lose some algorithm values with their images hosted elsewhere?
b) Search engine may find it unusual and a questionable practice to not have the site's images on same domain?
c) Would individual subdomains or one main image domain be the better repository for their images?