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/
In addition, help out your instance admins by resizing the image if you don’t need it in high resolution.
Uploading a 250Kb file rather than a 2.5MB one makes a difference when thousands of users are doing it.