Photos wrongly rotated

"Terry Pinnell" wrote in message
...
For photos taken in portrait mode, I sometimes find that their
thumbnails
are wrongly displayed in Windows XP Explorer folders as landscape, and
also when opened in IrfanView. But when opened in other some other
programs such as Picasa or my video editor, they are correctly shown in
portrait mode.

What is the underlying cause? Why do some programs manage to treat them
correctly while others fail please?

--
Terry, East Grinstead, UK

Terry,

The camera can set a flag in the file's EXIF data to say that the image
was rotated. However, this flag was either not present or not used in
early EXIF data (cameras typically did not have the information to
record), and early software did not bother to read that field and rotate
the displayed image accordingly. What version of IrfanView do you have?
I would expect that program to honour the rotation flag. Perhaps it's an
option you can set.

Cheers,
David