If the color count of an image is low such as when black and white
documents are scanned in color, PNG with lossy quantization may
produce a superior encoding to JPEG. This is expensive to test however.
* Fix unreachable code
This fixes an issue reported by LGTM.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
* Remove unused imports
This fixes several recommendations from LGTM.
Signed-off-by: Stefan Weil <sw@weilnetz.de>