Computers

The banner photo is 315 px X 851 px
The file size cannot be larger than 100 kilobites
You can use JPG files but PNG files get sharper results

The profile picture is square - 160 px by 160 px
but the is a frame around it 2 px wide
 
You need to upload a 160 px by 160 px profile photo but the 2 px around it is important to know if you are being creative and considering the frames effect on the background
 

There is a space of 16 px between the profile picture and the left side of the banner picture. 
and down 176 px from the top.
It hangs below the banner picture 25 px

This is the area that shows on your timeline

You can be creative and use a graphic program to make your profile picture seem as a continuation of the background.
The 340 px is important for the right placement of the area of the picture where your profile picture is copied from.
 
The picture you upload as your banner still has to be 315 px high.
 
After you have copied the profile picture area of 160 pix by 160 pix and saved it as your profile picture, you will need to cut off the 25 px at the bottom to make it 315 pix.