Hi Michael,
yes I know of these features, this is how I position background images. However it is still trial and error, and takes a few trials to get it right.
I would like to be able to scale by 2 point click, and also rotate them in a similar way as other objects (and not wiht the grips).

The problem is that right now I am working with the frame of the image, which is fine if there is another reference frame, but say I have as a reference in the drawing which i know is 20m long, it would be nice to be able to just draw a 20 m long line in moi, and then snap the image to this, and do a scale operation by snapping to the line object (this is how it works in AutoCad for exemple)