You add your logo to your invoices by going to Payment Center Settings tab | Customize Invoice button. To use the same logo on your payment pages, check Use Invoice Logo In Online Payment Page (please add the field to your layout if it’s not there):

Screen Shot 2013-11-22 at 8.42.50 PM

 

When the box is checked, your logo will appear in your payment pages, as shown in the screenshots below:

Screen Shot 2013-11-22 at 8.57.48 PM

Screen Shot 2013-11-22 at 8.59.34 PM

 

This feature is available in the November 2013 release.