Internal is defined as an inset in the larger image containing an, surprise, internal view of the action. x-ray, on the other hand, has no wiki.

My thought is to define it as such: images wherein parts of the characters bodies are depicted as transparent, so as to see what's going on inside.

This is different, because the inside view is on the body itself, rather than a secondary inset, but the bodies in the primary image are opaque.

So, internal
post #249358

and x-ray
post #247515

I guess we'll have to introduce medical_x-ray in order to separate it from that.