After some trials & errors i found the following:
Sheet Background doesn't work, will always scale as far as i can tell.
But when using a text box with image, it does work if you use the following settings for the text box:
Properties - General
(confusion came in part because very high brightness of QV admin desktop screen, because of this it appeared that the image height was cropped when using 'Keep aspect'. Actually is was a soft grey, but not visible due to bridgtness )