Facebook has made changes as to how images appear with link posts. The image selected to accompany the post, when more than 560 x 292 pixels wide, will automatically take up the width of the stream, which is significantly larger than the thumbnail size images than previously accompanied link share posts.
The result is a big improvement as larger images are much more engaging. This leads to more click-throughs, likes, and shares. The entire image becomes one massive link, which helps drive traffic. Here’s an example from the ABCNews Facebook page.
There are a couple of caveats to be aware of with this new addition. Facebook recommends image sizes of 1200 x 627 px to ensure that the larger image will appear. However, some pictures larger than the 560 x 292 size will still appear in thumbnail size. Before posting, be sure to test the post on a test page and then refresh to see if the larger size appears. Also, if you highlight the post in Facebook, it will lose its larger image size.
While this new features does apply to organic link share posts, of course, post link ads also benefit as do page like ads, event ads, and offer ads.
These changes make it easier for posts with a link to gain traction with the addition of new larger images for the posts. The added visual engagement also make for a more pleasing Facebook experience. Much more so than the smaller images seen previously.