In what preposition should I use when referring to a picture / photo description or a person who's located in / on one of its sides.
She is in the left side of the picture
Or
She is on the left side of the picture
asked Jun 19 '18 at 7:47
We normally speak of someone being in a photograph rather than "on". What may change things slightly here is that you are referring to a particular part of the photo, the left. We always say "on the left", never "in the left", as that is simply incorrect.
What you see as the left side of a photograph isn't technically the left. The person to the left in a photo was standing on the right when it was taken! So if you are describing a person's position in a photograph technically I suppose you should say "on the left of the photo", because you are referring to the printed photograph rather than what it depicts.
