ZB Ex: Rotate and Actual Rotate Images

What is the functional difference between Rotating an image using the EXIF data and Rotate Actual Image?

When an image is rotated via a tag in the Exif info, the image isn't physically altered to achieve the rotation. It's the browser program that recognizes this tag that actually rotates the image for you. If you use a browser that doesn't recognize the tag, the image is displayed as-is, unrotated.

If you opt to "Rotate Actual Image", the image file is changed so that the image is rotated and will display way that no matter what browser you use to view the image.

BTW, by "browser" I mean any image viewer and not necessarily an internet browser.

I have a related question.

I know some editors/viewers may do a bad job and loose image quality when rotating. Windows Picture and Fax Viewer is particularly bad, usually using more JPEG compression than the original file (and therefore introducing more JPEG artifacts).

How bad is PS Elements Organizer's rotating feature in this respect? Should we worry about it?

I've just tested it and noticed that files get smaller, so I guess there is also some loss going on...

I did some research and guess I find the answer for my own question... just in case someone wants to know:

"Most images will not lose quality when rotated 90 or 180 degrees. JPEG is the exception because of the way this format is compressed. Some programs can do lossless JPEG rotation, but it is unclear whether Photoshop is one of them."

Source:
http://graphicssoft.ab​out.com …aging/f/rotateq​uality.htm

"(...) it is possible to do 90-degree rotations and flips losslessly, if the image dimensions are a multiple of the file's block size (typically 16x16, 16x8, or 8x8 pixels for color JPEGs)."

Source:
http://clk.about.com …Dfaq%2Fpart1%2F​index.html

JPEGclub.org provides a list of applications which provide the JPEG lossless rotation feature. Incidentally, Photoshop is not on it.

http://clk.about.com …gcrop%2Flossles​sapps.html

Canon's zoombrowser can also "simulate" rotation by setting a flag in the EXIF data. That, of course, does not incur in any loss of information, but if your viewer doesn't support EXIF, you won't see the rotated image.

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Correction:

Photoshop does lossless JPEG rotatation whenever possible. If it's not possible, you get a warning.