You can now add a header image to your Twitter account through their web app
Twitter has rolled out an update to their web app to enable their users to add a header image to their user profiles.
This feature was earlier launched through their mobile apps for Google Android and Apple iOS.
You can now set up an image for your own Twitter profile here.
Header image on Twitter is similar to what we already have on Google+ and Facebook. Twitter requires an image at least 1252×626 pixels in size for the header image.