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/
If you’re into self hosting, this repository is simple to install and use for sharing images.
I feel like self hosted is where most linked images eventually disappear. Much more so than image hoster platforms - where it obviously varies too, some disappear.