Facebook timeline covers do best at 851×315 pixels and thats what these are, ofcourse the image doesnt need to be exact. These are beautiful covers and thats the theme of these ones in particular, scenic and vibrant colors. With mostly nature i belive this is a pretty good set and hopfully you will get some use out of them.

In addition to using these facebook timeline covers for your profile cover you can use them as group and pages covers aswell. Keep in mind that group cover photos are actually 801×250 which is a bit different so the image will look a bit distorted when using them for groups.
Timeline covers for facebook are:

Some beautiful mountains
A lone house with a great view
Lavender flowers growing
An amazing sunset
A red heart graphic
A poinsones fish
An autmn scene