I've noticed a pattern in the blog posts that I write about these #100DaysOfIndieWeb updates, which is that I almost always include a photo in the article, most of the time embedded in the text. When I syndicate these articles to Twitter, I was previously only including the name of the post and the URL to the post, but I wanted to include the photo as well.
Today I updated my syndication code to check for a "featured" photo when syndicating blog posts. It first checks for a "featured" property in the post's storage file. (So far I don't actually have any examples of storing it that way.) It then parses the post's HTML and checks if there is an image with the "u-featured" class. If so, it includes that image in the request to syndicate the post via silo.pub.
Now my syndicated articles will include an image!