Newstone theme also supports adding a featured image as the custom header image for specific posts and pages. How to do it? It is simple, just follow these steps below.
When you edit a post or page in the editor panel, you can find a widget called “Featured Image” in the right bottom side. Click on “Set featured image” link, then select an image or upload a new image.
Click on “Use as featured image”.
Now, the featured image should be displayed in your “Featured Image” widget.
Custom Header Image
Notice that, if you want to change the header image with a featured image, the size of the featured image must have width 960px and height 130px, or the header image will not be changed.
It is recommended to design a 960×130 image for changing the custom header image.