When I Survey The Heavens
The 5 x 7 inch size - Can be used on blogs and websites and to create a frameable photo.
The 8 x 10 inch size - Can be used to create a beautiful Wall Print or frameable photo or on blogs and websites.
The 16 x 20 size - Specifically sized to create a nice wall print.
1280 x 720 pixels is video cover size, however you can resize the picture to use in any way you like.