No image in Amazon Showcase widget

No book image shows up in my Amazon Showcase widget. Only the title text. I’ve had this widget installed for a couple of years and it’s always worked, though it gives me trouble like this once in a while. So I tried, as an alternative, pasting the Amazon link text into a text box, but that doesn’t show up either. If you look at my sidebar at https://thiefhunters.com you’ll see the text “My book of thieves on Amazon” near the top. (There’s another book icon down at the bottom of the sidebar that still works.)

Any insight would be appreciated!