Help with product archive image?

First off, forgive me, I am one of those people who knows just enough to get myself into trouble. I can usually fix my issues but then I forget what I did and I’m back at square one. So.

I am using WooCommerce. I created a custom product archive called Collections. At least, I think that’s what I did. I have an option under Products called Collections, and I believe I created it, I just don’t know how. Is that a custom taxonomy?

Okay so now you know my state of mind. This “Collections” thingy behaves like a typical product archive, except that I can’t upload an image. All of the expected options appear, but when I select “Add/Edit Image” I get this message at the top of the page:

Item updated
<- Go to Tags

But I never have the opportunity to upload an image. Other collections have images, so obviously this has worked in the past, but I do have a vague recollection of finding a workaround. My problem is I don’t document.

Thanks for following me for this long. Any and all assistance is most appreciated. I’m out of spoons this week and I just need stuff to work.

The page I need help with: [log in to see the link]