Samsung, or some third-party affiliated with Samsung has done goof. Samsung smartphones Galaxy S9 and even S8 have been reported to send random photos to their contacts. That can only mean one thing.
Your nudes are in danger.
As reported in Gizmodo and The Verge, the problem seems to be coming from Samsung Messages - Samsung's own replica of the Messages app. Galaxy phone users aren't even aware that their stuff is being sent until long after they've gone viral in their own social circles. It's creepy and wrong. And expect a ton of new nudes puffing into the internet's existence.
No one knows for sure why this is happening. According to The Verge, it might had been from an RCS Update from a foreign network. Which probably means, with Globe and Smart, and being in the Philippines, all your photos are safe from widespread ruin.
Moral lesson to Samsung, stop cloning Android apps that are already available from stock Android. It's just eating up storage space. And, ew, who uses SMS in 2018?