What are the YouTube Dimensions? Below is a list of Youtube features and their dimensions including video dimensions, profile icon dimensions and more.

Youtube Dimensions

1. Profile image icon or Avatar Icon displayed on the users channel profile page is displayed at 88x88 pixels. The avatar image is displayed on certain pages as small as 25x25 pixels. Youtube suggests you upload your avatar image at 800x800 pixels.
2. Youtube Channel background image should be as large as the maximum standard monitor resolution ~2511x2508 pixels. The Youtube channel content box takes up a horizontal space of 2390 pixles and a potentialvertical space of 970 pixels.
   Here's a background image template(click to enlarge):
   
3. The video thumbnail dimensions of the videos thumbnails displayed on the channels page are 320x180 pixels.
4. The default video embed dimensions that Youtube plays it's embeded videos in are 420x315, 480x360, 640x480 and 960x720.