Hot to get the PayPal button image to show?

I am using Pro Sites. My checkout page does not show the PayPal button image, only text.

Here's the screen shot illustrating the problem:

In the source code I can see that it's supposed to be the image at:

The reason the button is not showing is simple: the image URL is broken and times out.

Since this image is not showing, is there a way for me to specify my own PayPal image somewhere? Or, do I need to modify your source code to do that?