XnView Software

"Rotate images based on EXIF orientation" option is not good, because user has an illusion the image is OK, but it isn't and when he wants to upload it somewhere, or create a video, this image is not rotated correctly.

What about another option:

"Rotate images based on EXIF orientation and automatically rotate the image and thumbnail" - but do not rotate the thumbnails in browser, so the user will see the images are not rotated correctly.

Or perhaps the option "Rotate images based on EXIF orientation and automatically rotate the image and thumbnail" might work also in the browser, while loading/reading the thumbnails.

I agree.
I was getting mad trying to understand why the thumbnail in winxp was still not oriented, then I realized that this option of Xnview affects just the way you see the image and the thumbnail inside Xnview itself, but if you open it with other apps (e.g. paint, gimp, ...) the image is still not rotated correctly.
I'd suggest that when the option of auto rotating basing on EXIF values also changes the image file

This option should not be placed under "General" but under "View" to make clear that it only affects the display. And it should be renamed to "Rotate images according to EXIF orientation tag".

Note that there is a rotation symbol if a rotated view is displayed. To rotate the image and change the file, there is a function "Tools > JPEG Lossless transformations > Rotate based on EXIF value". This should be renamed to "Rotate according to EXIF orientation tag".

The inverse transformation should also be possible, namely a lossless rotation by only changing the EXIF orientation tag.

See also:
- EXIF lossless rotation
- 1.94.2: Option "Rotate images based on EXIF orientation