When accessing the image (https://neo.life/wp-content/uploads/2022/07/buck-institute-longevity-aging-genetics@2x-1000x714.jpg) programatically (e.g. via curl), we get served a Cloudflare error page with a captcha. So it looks like this site is deliberately blocking robots from downloading the images.
If you trust the site and are happy for images to be permanently hotlinked, then you could add neo.life to the disabled image download domains to stop Discourse attempting to download them.