Instagram uses phone camera for adverts?

So yesterday I organised some boxes I hadn't opened in years, using my iPhone as a flashlight. I saw and picked up an old Casio watch and put it in my pocket. I then took it to my room and didn't say a word to anyone about it. I never spoke or searched the word Casio.

That same evening I have been getting adverts for Casio watches on Instagram which I have never seen before. Can someone explain this?

adverts camera instagram phone privacy