Featured image broken link

I don’t know why, but for the first time, my featured image is coming up as a broken link. I’d say it was my woeful net speed, but I was able to download and upload other images within the body of the post with no trouble, but the featured image. no matter which one I’ve tried, all come up as broken links: http://itsgoingok.com/looking-for-iowa/
Can anybody help?
Thank you!