#[0]
I think some images after being uploaded aren't being generated with the extension in the 'Copy' URL:
https://nostr.build/i/nostr.build_cfaaa8739cad3e039d50de069664a1fe3c1ab775ead8bd2242bd7bc044396890.
^ For example that link was generated, you will need to copy and paste it into a new tab to see the image.