There are guides for recommended Facebook Page cover images all over the internet but accurate (and up-to-date) recommendations on GROUP image sizes are hard to come by. The traditional Facebook Page cover images (we call this the "letterbox size") is 820 x 312 pixels. On these designers need to be careful where text is placed on the image because it will often be cropped on mobile or have Facebook-imposed text sitting on top of it. Facebook GROUP cover images are different again. Fac...