The double attack and x-ray attack (Gold collection)

Hmm isn't it like this?

Pin: An attacking piece pins a less valuable enemy piece to a more valuable enemy piece because they are lined up in a line of fire.

Skewer: An attack that forces a more valuable enemy piece to move but thereby uncovering a less valuable (mostly) undefended piece behind it. (Isn't it also called skewer if two equally valuable pieces are skewered in a line of fire?)

X-ray attack: A threat of being in the line of fire of a rook, queen or bishop. In this case there are enemy and/or friendly pieces between the attacker and the target.

Skewers are only skewers when the attack is actually played. Xray attacks can turn into skewers or pins but xray attacks are more a threat what may come in the future then an actual attack isnt' it?

I think the OPs xray picture is more a skewer then an xray attack. But heck I might be wrong. Anyone an expert on this?