Like many designers, I've had to search for cover photo dimensions for social networks countless times. Facebook, Google, and Twitter cover photo dimensions are all different, and I'm tired of continuously hunting for all these cover image sizes. This guide is meant to help make designer's lives a little easier.
The optimal size for a Facebook Timeline cover is 851px x 315px, though Facebook automatically scales and crops the Facebook Cover Photo size to fit the container.
Does anyone else find it peculiar that Twitter requires you to upload a 1252px x 626px cover photo for a 520px x 260px container? I'm wondering if they've got a nice redesign coming up. Either way, the Twitter header size is 1252x626px. Twitter automatically resizes profile pictures to be no larger than 500 pixels.