>
> As you know, 'convert' also can rotate an image.
>

Yes, it probably can, but as I remember it, the rotation is lossy, i.e. it
makes the JPEG data worse than before the rotation. jpegtran was able to do
lossless rotation, which is why I picked it. For thumbnails it would not
matter but for rotating original files it's not nice to loose
information/quality. As long as users can get hold of jpegtran I think it
should be the default program used for rotation.

I will keep testing during this week.  Then, if everything is OK
> i will push the patch to the Emacs repository.
>

Sounds good, thanks for doing this!

/Mathias