Orientation problem? Is there an extra tag?

[mnasdaq]

Hi!

In 2009 my father used to use a arcsoft-software; after that he switched to Picasa (Windows) and now to Shotwell, Ubuntu 12.04.
I dont know if he used any other software to rotate the pictures, but its a fact that all photos till 2009-11-11 are displayed in wrong orientation (in any program). After 2009-11-11 its ok (with a few exceptions).
My question is, how can i display all photos in right orientation (in all programs + WDTV Live on his TV).
Is there an EXIF-Tag, that  applications lets rotate the photos automatically by the orientation tag? And others not?

I'm very desperated...hope you can help me - there are over 20 000 photos to process and dont have a clue and even not enough time...

Thanks in advance

Mnasdaq

[Phil Harvey]

ExifTool GUI allows you to rotate JPEG images according to the EXIF orientation tag.  This may do what you want for at least some of the images.

- Phil

[mnasdaq]

Thanks, that worked for all files up from 2009-11-11.
Do you have a proposal for rotating the photos before that date?

[Phil Harvey]

If they don't have orientation information, then they will have to be rotated by hand using an image editor (with a lossless rotation feature).

- Phil