Auto width for images?

I use an image at the top of my screen (something like a blog), that I would like to always fill the width of the screen.

Is there any option to set the image width to 100% rather than to a specific width size? I understand then height would also change, which is not a problem.

If not, are there any workarounds that might help?

Set the image’s width to the full width of the screen and desired height.

Set the image cropping setting to “Crop Image to Fill Space”.

This is the closest you’ll get. This will not adjust the height of the image, only ensure full-width of the image.