A while ago, Andrew helped me with Custom CSS for adding a Header background image. I tried replacing it with a new one, but it doesn’t scale properly. It is currently 1080×216. When the window shrinks, rather than scaling, the image is truncated.
I need to know what size to create the image, so that it properly fits/scales on the various screen sizes that I need to support (desktop browser, tablets, phones…)
And is there anything else I need to do to get it to behave responsively?