Inappropriate images while seems less bad than porn, but after a while one’s mind gets bored with it and wants more stimulus and wonder of to bad sites. I am unsure 100% about porn, but with masturbation, I heard / read from number of places that excessive masturbation could lead to loss in sensitivity down there, which would unable one to reach orgasm when doing it normally with one’s wife. With porn likely one would unable to be psychologically be satisfied (a lot of it is super edited). But the worse things are urges for it and inability to stop when wants to. My advice stay away from these type of stuff, once trap in it, it’s hard to get out.