I usually rotate all my jpg photos (using Windows Photo Viewer) after removing them from my camera's card. Is this correct? Am I losing quality for rotating them? Should I just leave them as they are and later incorporate the rotation as another retouch step - at a post-processing software like, for instance, Lightroom?
Sometimes I see websites like DPreview.com showing their camera's sample photos not rotated, thus I thought rotating them would reduce (a lit bit) their quality. It it a fair assumption?