I can see Will's banner. Something is wrong with yours. Does your host server allow other servers to downscale the image?
Discussion
no clue, on snort i can choose between void.cat, nostr. build and nostrimg.com. I can try uploading the other two... Have only tried void so far, it encoded it into a webp
no difference, imgbb.com, nostr.build, nostrimg.com and void.cat all make the banner appear on snort and iris but not in Amethyst 😕