Honestly, it was a pain in the bum to get these images consistently out of the CMX viewer. Every time I changed car, all the CMX settings were reset, including lighting, background colours etc. The only way to do it quickly and effectively was to pick the left side view (adequately lit by default light heading etc) and screenshot.
We can't render skins on the server because we can't invoke the required 3D rendering engine over RDC. We did have a plan, once upon a time, to render userbars with cars skinned in the individual's last used skin, but it turned out to be impossible for us to do