Because cubeupload was giving me trouble with the email verification, I went the alternative route and got an ImgBB account instead. Apologies to Gilbert if he can't see them, but at least I can upload images on-demand and use them here!
Someday I might make a ImgBB proxy, but first I need to find a server to host it…
Signs point to no. It seems like the filter is on an lower layer than the DNS.
Welp, I jinxed myself. Putting the IP on /etc/hosts
seems to partially fix it.