Q: Icloud photo issue

This morning I was on my icloud photos on the iphone and found photos that are nobody I've ever seen of a mom and a kid. I tried to check the geotag on them but has no info available on where it was taken... all my device at that timeframe were in my house so no device took this photo. Should i be worried my account has been taken over ? or is this a crazy glitch ?

Also all my device are not previously owned and bought directly from apple, was reading a few forms regarding issues of previous owners history.

Thanks,

dimerbox