The TLS Certificate of the attachments.f95zone.to domain has expired yesterday. That's why the images don't load.
If you right click the text where it says the filename and click open image in new tab, you will see the TLS warning of your browser and can explicitly allow it.
After that images will load again, at least on Firefox and only for as long as you keep the browser open. If you close the browser session and reopen it you'll have to take the same steps again.
This is only a workaround, not an actual fix to the situation. Fixing this is up to the F95zone admin(s) who have access to the server and can check what's up with their Let's Encyrpt setup.