Hi okapi, unfortunately it is tough to make the regular tools work on images - the regular tools work on the selected objects.

If you could select images as you could normal objects, they would frequently get selected instead of the objects that you are working on since they take up a large area of the screen. They would just easily get in the way of operating on your objects.

You might try creating a rectangle or line curve as a reference object, scale it to the exact size that you need and then snap on to it when scaling the image.

If you create that guide line initially before you even place the image, you should be able to draw the image in at the correct size when you initially place it.

- Michael