I'm not sure how I could accomplish rotating a picture w/o using this add-on. Other than perhaps download the picture, delete the existing attachment, rotate the picture while on my PC, then re-upload it once again. Talk about a Time-Saver, this add-on is a godsend when you need it!
With so many users snapping pics with their cellphones nowadays (many with an in-phone autorotate function), you are bound to have a real need for this add-on if your forum encourages members to upload their pictures.