Have you ever rotated (turned) a picture from your digital camera, or any other image, in an application in Mac OS X 10.4, only to find the rotation does not remain when you open it in a different application or on a different computer? We'll explain why that might happen.
Mac OS X 10.4 Tiger supports image rotation according to EXIFstandards. Earlier Mac OS versions did not support the EXIF standard.
This means that, in earlier versions, saving an image after rotating changed the actual pixels of the image file. However, this was often not desirable because rewriting the image file itself in the new orientation could degrade image quality (especially with lossy graphic formats such as JPEG). With EXIF-compatible applications, if you rotate an image, the file doesn't need to be rewritten.
Non-EXIF compatible applications display the image as it was originally created. EXIF-compatible applications use an Orientation tag to determine whether the image needs to be rotated before it is displayed. The image is rotated and displayed in RAM rather than in the file itself, so no change to the original file data is made.
If you want the image to appear rotated regardless of which application opens it, you'll need to open it in an application designed to save images for non-EXIF applications, rotate it, and save the image (with possible image quality loss).