Go to the pic you want to post,click edit. Choose the rotate option. Rotate the photo until it’s upside down, click save. Choose edit again. Rotate the photo again so it is right side up, save. Hopefully this will take care of your sideways pics. It works for me.
Right on! Looking forward to right side up pics in the future. Lol. iPhones are famous for that I figured you had one cuz I do too and have experienced the same issue. Glad that I could help. 🎣