The page gives you guidelines on adding channel art to your Youtube account. It will allow you to optimise your header for smart TV, phones, tablets etc.
How it works on Desktop
The below slice would be your desktop banner. It’s total dimensions are 2560 X 423 px.
How it works on TV
How it works on Tablets
New channels will have a flexible width on desktop, meaning that the site will scale to reveal more content on larger browser windows. There is a minimum size at which point the site would no longer adapt and a scroll bar would appear in the browser window. At the minimum width the channel art is 1546 X 423 px (this is the “Safe area” given that text & logos will not be cut off). At the maximum width, the channel art is 2560 X 423 px. This means that the “SAFE AREA” (channel art at minimum width) will always be visible and the areas to the right and left (shown with green arrows) might be visible depending on the viewer’s browser size.