@CannaBliss @meganpaasch the metadata which was scrubbed for privacy when the pic was uploaded includes the device orientation info added by the camera when the photo was taken. e.g a portrait photo is actually saved as landscape with a note saying to display it with a 90⁰ rotation.
Editing it and re-saving makes that orientation property redundant, i.e it changes a file that's saved as "1920 × 1080 with 270⁰ rotation" as just plain "1080x1920" so it's displayed the right way up by default.