Uploaded image gets rotated in wrong orientation

Appian does not modify your image in any way. If you need to rotate it, there are plugins available.

Try using a different image to check if the others are being rotated, Or use a different image component like a!webImage() to see if the images are still being rotated or not, there must be a plugin that is rotating the image orientation that you need to troubleshoot.

As Stefan points out, no alteration has happened to your image.  What you may be experiencing is the fact that many cameras (phones, etc) will store the orientation of a picture as metadata rather than actual orienting the image in a particular direction, and the Appian Image Display field may not always observe this metadata.