Facebook has made larger images a standard for all link share posts. As stated by Facebook, the goal behind this change is to make stories look more beautiful and to increase the click-through rates on links with more engaging, larger images.
Now onwards, when you will be uploading the images to accompany an article, Facebook will recommend you an image size of 1200×627 pixels. The minimum approved image size for link share posts is 560×292 pixels.
Apart from this, larger images are also new standard for Page like ads, offer ads, Page post link ads, event ads, and offer ads.
When you will post either of these, the new image format will turn the text box and image into a massive link, which will be pointing people to respective website.Facebook Increases the Image Size for Link Share Posts!,