Most publishers who care about maximizing traffic to their websites take advantage of their visitors’ sharing habits on social networks. In its most basic form, sharing takes place when a reader copies the link for a page they liked, and pastes it into a Facebook status update or a tweet on Twitter.
Until a month or two ago, when a user shared a link on Facebook, it seemed typical for the network to offer up a preview of the share that included a choice of images based on the images contained in the post. Facebook provides these image choices in a couple of different ways — first, it looks for publisher-provided Open Graph tags in the HTML of the link being shared; then failing to do so, it will scan the page’s HTML itself and select a few likely candidates that may or may not actually have anything to do with the link’s feature content.
Using the Open Graph method is easy: simply include at least one og:image property in a page’s HTML <head> section:
<meta property="og:image" content="http://www.exampleapp.com/playlist/ID/image" />
It has been common practice for publishers often to include multiple og:image properties for a page. The result is that users sharing the content can choose, within Facebook’s sharing preview pane, which image they want to see next to the post wherever they’ve shared it.
Recently, however, it seems like that’s no longer an option — we recently reviewed the og:image tags we were putting in our site (WordPress.com VIP was inserting a blank image as the first one, which was a different issue we fixed), and discovered that Facebook was only using the first one – without giving users a choice to use any of the others that some of our posts include.
My Google/Bing-foo must be off, because I can’t find any indication or confirmation that Facebook has actually changed the way it processes og:image property tags; but suddenly, I’ve noticed that many sites only include one og:image property tag, and that our site’s content is not the only one that no longer offers multiple image choices when it’s shared on Facebook. In fact, the only content I’ve found for which Facebook has presented more than one option was from pages that don’t contain ANY og:image tags.