Random header image

Hi. I am building my own theme. I have a section in the header where an image should show up. I would like to manage these images within WP. What is a good way to automate this within a theme?

I thought about making “pages” with the URL of these images and then randomizing those pages through PHP in my header.php template, but that doesn’t sound very clever.

Any ideas on what is a smart and efficient way of randomizing images?

Thanks!