These photos are taken from the internet: https://www.google.com/search?safe=off&q=best+things+to+do+in+porto&tbm=isch&tbs=simg:CAQSlwEJchLb90tjHQ4aiwELEKjU2AQaBAgVCAkMCxCwjKcIGmIKYAgDEij_1FLgK6B3VFPwU_1hTUFNIUpgPQFOU-uiLDOLoq5j6gIL4imSq1KpMqGjAY2U-St2cSMWz3QDA4LmLWRxg2P7vvFWlOKsWsJ1RkHFRWO95D0ecf_1rdsXJ6tGL0gBAwLEI6u_1ggaCgoICAESBJn3HjoM&sa=X&ved=0ahUKEwjam4nNlrrZAhVKyWMKHfWTCYkQ2A4IJygB&biw=1799&bih=925
Really? Оo.. And where was the opposite asserted?
By not citing you are lying by omission. It is still plagiarisation, which will get you blacklisted if certain bots come across it. Please source/give credit to the actual photographers when posting other peoples work. Making money off other people's photography is called copyright infringement.
I understood you.