Why does my header/cover image change back every time I change it?

This is likely just a cache issue with your browser.  

Try opening a private/incognito window in your browser and viewing the page. You can also restart your browser, manually clear the cache, or just wait a bit for your browser’s cache to expire. You could also try viewing your website using a different browser, different computer, or mobile device.

Additionally, our CDN caches your images/artwork, and it can sometimes take a few minutes for the cache to be purged.