(mods, please feel free to move this post to a different thread if you think it's a better location! the FAQ thread was my first choice but it's closed. i've posted these instructions in various picture-heavy threads in the past, but they get buried and there are a lot of new people lately.) so the forum software sometimes rotates people's photos after uploading! and this can be really annoying! BUT, you can get around it! here's how: -open the photo in any photo editing software. -rotate the photo to an incorrect orientation. SAVE the file. -rotate the photo back to the correct orientation. SAVE again. and now when you upload, it will post correctly! i am PRETTY sure this works with most mobile software-- i don't post from mobile very often, but the handful of times i have, i was able to do the rotate-save-rotate again-save trick in the iphone's default Photos app and it displayed correctly. GO FORTH AND POST CORRECTLY-ORIENTED PICS
https://xenforo.com/community/threads/attachments-rotated.48091/ Xenforo isn't processing one of the PNG tags correctly. GIMP is smart enough to ask about the rotation and let you save a new PNG that doesn't have the rotation thing, other things might not be.
i mostly use Preview, the basic photo viewing application for macOS, and it's always worked. i THINK when i first discovered this trick i tried with a few other things like Photoshop, but Photoshop takes forever to load so i don't usually use it for something so basic.
Can confirm that it works on iOS! (And major thanks for this thread, @hyrax--it's good info to have!)