ID:154762
 
Is removing an image from mob.client.images the only way to remove images from a mob?

If so, that means you can't remove them from an NPC, so is there any other way to deal with invisibility to certain groups of players?
Since NPCs don't have clients, they don't see images. You can't show NPCs images, and you can't hide them from NPCs. You can attach images and detach images on NPCs for clients to see, but the NPC never has any reference of them.

What exactly is the problem?

Whatever it is, this library should help with what I'm guessing your problem is.
http://www.byond.com/developer/Forum_account/ VisibilityGroups