When people post links to jenkins.io blogs to social media like Facebook, Reddit, or Twitter, an image in that page gets picked up as the thumbnail image.
All too often, the "fork me on github" ribbon gets picked up for this purpose, yet that's undesirable. I believe there's some metadata we can put on our HTML so that at least it picks up our butler logo. Obviously, if a post has a better more meaningful image (such as a screenshot), that should be picked up.
I'm going to attach the screenshot from my Facebook.