[rosndo]

OP most likely realized their mistake and deleted the thread instead of owning up to it.

The thread was deleted by the OP, not removed by moderators (reddit visibly differentiates between the two)

[bellyfullofbac]

OP replied in the comments why he deleted it: https://www.reddit.com/r/NoStupidQuestions/comments/rxtl22/w...

TL;DR: he's an idiot.

A bit longer: OP went to a shop to get his phone repaired. Shop gave him a loaner phone, which had been used by many many people and apparently never wiped. OP set up Google backup on that phone and those photos got uploaded onto his WhatsApp backup. OP got a new phone, set up WhatsApp, and WhatsApp downloaded the pics from the loaner phone onto his.