Image not saving

Site URL: https://www.aarontempler.com/book

Hello! First time member here, still learning the search terms, so thanks in advance for your patience if this is a repeat.

Today an image disappeared on one of my pages: https://www.aarontempler.com/book

Oddly, it shows up when I go to edit the page: It seems as if it's there in Edit mode, but it won't save. When I click Save and exit Edit mode, it disappears again. And it does not appear on my site.

Has anyone encountered this? Using Safari 14.1 on Mac OS 11.3.1, Personal Plan.

Thanks in advance!

I should also mention that I tried deleting it and inserting it again with no luck. 

Is this a book cover image?