No idea. Why not? They are just regular image links.
Images uploaded in Amethyst are not visible in all other Nostr clients!
nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z what happens?!
Discussion
Looks fine to me... 
There's some additional info in the image link since last big update, files not necessary ending with a file ending which might be a problem for some clients?
Like this:
For example: This is an Amethyst image not visible on Primal
#m=image%2Fjpeg&dim=1049x1920&blurhash=%5D55%3A%3A7%3DfR%24i_WA%7DI%24koIniaeXgt3r%40jFnj6IX3w%7DjYsCKHf%24sDWBn%2BR*a%23offkWVWVR%2BS2bIW%3AI.NaShX8W%3BNHNaS4S%23X8&x=0c1b2454008bd3fcc94dbfbe84044833dce51e7acaf5e84db4921bba01884d17
Probably they just need to adjust their algo to remove # fragments before trying to identify if the link is an image or not.
But the real way to solve this is to ping the server to download the opengraph preview and checking the content type before downloading the image.
I don't see this in amethyst