"J. P. Gilliver (John)" wrote:
[...]

For example, I know there are lossless, for example, _rotations_ for
JPEG,

For any decent renderer, JPEG images do not need to be rotated,
because the orientation can be set by bits in the EXIF part of the JPEG
file.

IrfanView - or possibly one of the plugins for it; I tend
to think of the combination as just IrfanView - offers lossless JPEG
crop and rotation.

IrfanView is an example of such a renderer:

Options - Properties/Settings... - JPG / PCD / GIF - JPEG-Load: -
tick 'Auto-rotate image according to EXIF info (if available)'.

I don't know if IrfanView can 'rotate' a picture by changing just the
EXIF info and not touching the rest of the file. It probably can, but I
didn't find it straight-away (I use other software to 'rotate' JPEG
pictures).