Samsung Cloud is not secure
I bought my Galaxy s7 Edge for the camera, and I take a lot of photos. I don't put them in separate albums often, so I often have hundred or more in the "camera" album. Yesterday I went in to cull it out. I'm still stunned by what I found. There were 38 photos from an unknown source, several of them lewd, bordering on porn. The rest of the 38 varied, but it was a group of young men and their family/associates that I do not know. A semi-automatic rifle starred in one. A baby covered in loose large denomination bills in another. There are a couple of screen shots of texts with phone numbers. My first impulse was to delete all of it. I haven't because I want answers.
My first s7 Edge was stolen early this year. At that time, I contacted AT&T to kill the phone, was assured that it was dead and not in any way traceable to me, although all data on it was lost, but now I wonder. I didn't have any security or backup on the stolen phone, so when I got its replacement, I signed onto the Samsung Cloud, which backs the phone up regularly when it is charging. I can't figure any other way rogue photos could get onto my phone, and I think the stolen unit is still connected to me somehow.
This is my first outreach for help in solving this mystery and putting a stop to it. I'd call these photos pornography, but they aren't artistic, just gross. Which really isn't the issue here. How is this happening?