returns a 404 file not found error.
But the real problem could be that the images are huge: 7272px × 10780px
Use an image editor to compress the file to a sensible size for the web—Pilcrow displays images with the 2 column layout 499px wide. By uploading such large files, you are wasting your storage space, and making the load time very very slow even to the point of the download timing out so the image cannot be viewed.
Make the image smaller (499 px with a resolution of 72).
Try deleting those big images from the library, and re-upload the smaller file with a new name to the page.