Where to report gThumb bug(-ette) ? Gnome or Ubuntu?

[Chanchao]

When taking a picture, my camera puts the picture orientation
(horizontal/lanscape or vertical/upright) in an EXIF field. 

gThumb supports this, though the initial view shows the picture 'the
wrong way' for upright pictures. This is fine in itself, as gThumb can
use the EXIF information to automatically do a lossless-rotate depending
on the picture orientation.  After that all the pictures show fine in
gThumb.

HOWEVER, it then doesn't update the EXIF value, which still says that
the picture is vertical!  So, when you then use the picture in other
software that supports picture orientation, it has no way of knowing
that it's already been rotated, so it will rotate it again to display it
in a way that the EXIF value still says is appropriate.

So, I think gThumb should clear/swap the EXIF orientation setting after
the lossless-rotate.

Do I report this at Ubuntu or at Gnome, and if so, where exactly?

Cheers,
Chanchao