A "header picture" refers to the image or photograph displayed at the top of a webpage, document, or social media profile. It serves as a visual representation or branding element, often spanning across the width of the page. Full definition
I picked «discipline» a couple years back, but sorta crashed and burned with that one I listed several words I hope will describe 2012 on my «new year» blog header picture... but now to choose just one.... (theletteredcottage.net)