I have scanned images at 300 DPI and 24bit color. Jpeg max quality.
Just want to rotate (land/port) - nothing else. Using the inbuilt Image Conversion via r/click on jpg file.
Select the single rotate option and it rotates.. Good.
But it changes the 300dpi to 96 dpi. 24bit color remains. File size dramatically reduces. Bad.
Happens on any file.
The Convert checkbox is unchecked, but on form the "JPEG Quality" value field is left active. It is reacting to that even though option should be ignored as per checkbox. I can put 1 in there and it is used.
In all cases the 300 dpi is dropped to 96dpi. Which is serious.
The DPI value in JPEG files is usually fairly meaningless, and doesn’t mean the number of pixels in the image has changed. Most software doesn’t read or write the value at all, but if it is used it would only determine the default size when printing, which can be overridden (and usually is, since it’s rarely meaningful and almost always set to 96).
As an alternative, you can adjust the EXIF rotation field via the Metadata panel, which won’t modify the image or other metadata at all. (But not all tools respect the field.)