Unfortunately, it looks like there was a problem with clan icons and images. They seem to have disappeared from the Amazon S3 bucket where they're stored. I'm not sure how this happened yet, but I am investigating.
In the meantime, if your clan icon isn't showing up, please ask a clan manager to re-upload the icon via the clan upload page: https://www.warlight.net/Clans/UploadIcon
I am sorry for the inconvenience. I am going to be looking into this further to ensure it can't happen again.