When you change the blog’s header image - what occurs with the original image you are changing away from? That context should be explained, and, I’d like to see the prior image still accessible from within that same area in the menu.
I believe they remain on the server in /content/images
There really needs to be a way to delete them internally
I agree with both.
Keep should be default, at least for the past two headers. With the option to delete any of them.
Here’s a summary of the state of media management in Ghost: