You can place the graphic in the header and then drag it out to cover the whole invoice. However, I could not make it transparent: either it is in front of the other printing, obscuring it, or it is behind and is partly obscured by the printing.

Judith is trying to generate a watermark styles graphic in the body of the invoice. I suggested using the printer software itself, or creating an invoice section with a different style code so that the BMP only prints once.