Imgur now blocks several VPNs and have issues loading embedded previews in several fediverse platforms. So instead of using imgur, you could use one of the following alternatives for uploading your images.
https://postimages.org/
https://imgbox.com/
https://imgbb.com/
https://www.imagebam.com/
A downside to hosting images externally is that these image hosts can go down before the Lemmy instance does, leaving many posts without context. One should keep this in mind when choosing where to upload their images.