Turn off iCloud Photo Library, or figure out who you are sharing your Apple ID with and make them stop using it.
Its not normal to have photos appear you don't recognize, it's not like it's a glitch you can fix with some established steps. If you are not sharing your Apple ID with any one, then it's something else.
We would need to figure out what is happening exactly to provide an actual solution. where where you browsing your pictures? Are you using the Apple Photos apps or are you using something else to browse them? What steps do you follow exactly when you browse your photos and you see the strange pictures?