gthumb and Nautilus automatically rotate images
I have some pictures which were taken with the camera held vertically, I've put them on a webpage, and they are displayed with the wrong orientation. How can I modify them? If possible I'd prefer not to use the GIMP, and I'm sure that it is possible, because I'd use to do that with gthumb, but now gthumb and Nautilus rotate the pictures automatically, so I don't know how to do that. I'm still on Gutsy.
I've discovered how to display a single picture "as it is": I go to tool > Reset Exif orientation tag, but I still don't know how to do it for all pictures on a directory.