GIMP#14 Channel Art Specs: Youtube One Channel (Gimp 2.8)
Youtube is moving everybody toward their new One Channel design, and one requirement for anybody who cares about their brand is proper channel art backgrounds that work on various size devices. I have created a specs file based on their official specs, but with pre-made layers for each size device, as well as mask layers.
The video shows how to use both mask layers and the logo-safe layer. The biggest additional hint is to look at your original image and decide whether preserving all of the vertical or all of the horizontal is most important, then scale your image accordingly. The full size image is supposed to be 2560x1440, and it is best not to skimp on that or scale up a smaller image. This Gimp file may be shared with others, but I'd prefer credit and a link to the lesson at http://mini-lessons.info/Gimp14
Stock image of industrial decay from http://fav.me/d5gdp4l courtesy of Malleni-Stock.deviantart.com