Hide attachements and images from select groups

I am in desperate need of a way to hide images that have been inserted into posts after they have been uploaded as attachments from certain groups. My forum requires a membership fee to view content, but if guests and members can see every inserted image it defeats the purpose. Previously I was using the Cloak mod to do this but something appears to have broken it, so it no longer properly hides images. It would be great to have this as a builtin feature like many other forum software do.