Pictures of other girls

I've been talking to a boy from my school lately and I've got to know him pretty well. He likes me a lot and he's very nice. I told him to screenshot his camera roll and I found a picture of a girl's ass and I felt very uncomfortable. He screenshoted the girl off sc while he liked me and said he felt bad and it was a mistake. Ik we aren't dating I just feel uncomfortable that he may actually be a douche, he told me it's something every guy does but I don't believe him. Please leave ur opinion that would be much needed :)