Getting my background to scale in a predictable way

I have an image that is 1217x601 (don't ask why, I'll find a different resolution for it at some point). But when I put this image on my game intending it to be the background for my scene it's displayed with a huge margin around all sides.

In the image example here the screen size is 1207x679 so I would expect the graphic to crop on the top and bottom and not quite fill the width. Either that or it would scale to fit vertically and then leave a bigger gap on the sides. Either of those I could see being reasonable outcomes, however the results below are what I get.

Also note the inspector values on the right are those currently being used for the background game object.

Additionally, here are the camera settings for the scene

Please, help shed some light!

Thanks