Pasting images into confluence saves, but show up as broken thumbnails when you edit the page

Question

Sometimes when editing pages and pasting in imagery from the clipboard everything seems fine but when you save the page and edit it again all the images show up as broken. You can click these and switch from the thumbnail back to the original image which displays, but if you then set it back to the thumbnail it breaks again:
Interestingly, if I inspect the image and copy it's source it gives me this url:
https://thanxapp.atlassian.net/wiki/download/thumbnails/429752520/image2018-7-11_19-55-20.png?version=1&modificationDate=1531364122223&cacheVersion=1&api=v2&width=200

But when I actually open that url, I am redirected to:

https://thanxapp.atlassian.net/login?dest-url=/wiki%2Fdownload%2Fthumbnails%2F429752520%2Fimage2018-7-11_19-55-20.png%3Fversion%3D1%26modificationDate%3D1531364122223%26cacheVersion%3D1%26api%3Dv2%26width%3D200

and this screen appears:

CARLISLE_9wxp32 · Answer

https://community.atlassian.com/t5/Confluence-questions/Images-Networking-DB-Programming/qaq-p/982696

See continued discussion on images in Confluence

Tinker Fadoua · Answer

Hmm this is a weird behavior. Since you are a Cloud user, i know that there isn't much you can do from your end. Please click here and open a ticket with Atlassian

Aaron Newton · Answer

Also, when viewing the page, the images are visible. Editing a page and selecting an image and choosing to show the original, or, indeed, one of the other sizes (the different size thumbnail choices) allows you to see the image in the editor. But the smallest thumbnail size is a broken image. Saving the page in this state works fine and you can see the image when in view mode.