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/
Files from Catbox seem to always be slow to load for me
They are a lot smaller than something like Imgur some they probably don’t have worldwide CDN to distribute images, so it will probably depend on the location where you are, but their offering of public API defintely outweights any possible slowdowns for me.