When tweeting, communicators only add an image if it’s explicitly called for.
For example, if we’re commenting on a facepalm by the White House chief of staff during a speech by the president, it makes sense to include the priceless picture.
Yet, for the vast majority of content, most users don’t think in visual terms. Instead, the link is tweeted out along with some text—and that’s it. Many major websites allow their links to automatically unfurl, thus providing a preview of the link without having to click on it. (This preview includes the headline, a one-sentence excerpt, and a cropped image.)
For most people, this process is good enough—and easy enough. Yet, three news outlets tweet a different way. Instead of allowing auto preview to do its thing, these publishers—@Mashable, @NRO, and @Slate—prefer to override the default settings and manually specify the picture for each tweet.