Hi,
When you add a background image to the desktop breakpoint, it then shows the controls (height, width, position, etc). However, when you are making the site responsive for all screen sizes, the controls are not available and you have to upload the image again in that breakpoint to open the controls again.
This logic might have been applied as a best practice to make sure you are optimizing images for each breakpoint, however sometimes you do not need to use a different image, so the ability to access the controls without having to add a new image would be great.