JTR over at The Art Of Not Asking Why describes a problem—and its resolution—that I didn’t know existed. The TL;DR is that photographs taken with an iPhone are always captured in landscape mode but Apple’s software detects portrait photos and corrects the orientation on the fly.
That leads to the problem: when iPhone portrait mode photos are shown on Linux using Org mode they are shown in landscape mode. You can get the details from JTR’s post.
The fix is pretty easy. He uses the mogrify tool of ImageMagick to auto-orient the photos based on their EXIF data. Since he’s viewing these photos in Org mode he wants an easy way of making the conversion from within Emacs. That’s a perfect job for Álvaro Ramírez’s dwim-shell-command, which JTR uses.
Take a look at the code and see how simple it is. Even if you aren’t an Elisp expert, it’s easy to do things like this with dwim-shell-command right from Emacs.