(
One more update, I just realized that in the Photo collection editor, clicking on the arrow on the top right opens the original, upload URL of the image (an unrelated domain I own).
By contrast, the published collection images start with https://uploads-sl.webflow.com (which 403s, see prev post).
Is this really the intended behavior? I thought the Image.URL field was used to fetch and store the image locally. And the published collection seems to agree with that.