Turn on Background Graphics

Internet Explorer

Setting the default behavior in Internet Explorer 7 and up; Background printing is usually already unchecked.
In IE, if your toolbar is not visible (Windows 7), hit the Alt key to reveal it.
Select Tools
Select Internet Options
Click the Advanced tab
Scroll to the Printing section
Check Print Background colors & images
Click OK

You may also need to check the browser settings under Page Setup.
In IE, if your toolbar is not visible (Windows 7), hit the Alt key to reveal it.
Select File
Select Page Setup…
Look for the Paper Options section in the top left corner
Check Print Background Colors & Images
Click OK

Firefox
In Firefox, if your toolbar is not visible (Windows 7), hit the Alt key to reveal it.
Select File
Select Page Setup…
Under the Format & Options tab
Check Print Background (colors & images)
Click OK

Google Chrome
Click Alt-P to bring up the Print dialog
Click "+ More settings"
Check Background graphics
Click Print

Safari
In Safari, if your toolbar is not visible (Windows 7), hit the Alt key to reveal it.
Select File
Select Print
From the Copies & Pages menu select Safari
Check Print Backgrounds box
Click Print