Facebook Timeline, is one of the new features that you’ll see the ability to add a large “Cover” image in Facebook. You can also see your friends cover images if they already switch to Facebook Timeline.
What is a Cover Image?
The Cover image is the large image that appears at the top of your new Timeline. This is your place to get creative and let your friends and extended community know a bit more about you.
My Facebook Cover Image snapshot
Facebook Timeline Cover Image Dimension / Size
When you try to upload a new photo for your facebook Timeline cover image, facebook will resized your picture. In Facebook Timeline cover image its better if you use minimum image dimension of 720 pixel wide and 300-350 pixel height with high resolution.
By default your cover images are public just like your profile pictures. This means, anyone can see your Facebook Timeline Cover Image who click on your profile picture.
Note : Still, there is no extra rules for using Facebook Timeline Cover Image except the basic facebook rules. Just for the curtsey Facebook will show a message, when you will try to use facebook timeline cover image at first time like below picture