The best default is to handle orientation automatically using the image’s EXIF orientation data when you create the thumbnail. Many phones store the “correct” rotation in metadata rather than rotating the pixel data itself. If your thumbnailing process strips EXIF, the thumbnail can display incorrectly even when the original looks fine.

So, when generating thumbnails, read the EXIF orientation and apply that rotation to the thumbnail pixels before saving. That way the thumbnail displays correctly even if metadata is removed.

A manual rotate option can still be useful as an extra editing feature, especially for unusual cases or intentional rotations, but it should not be the primary fix for normal uploads.

Doing nothing is not a good choice, because wrong orientation is usually a metadata-handling issue, not an artistic decision.