Keep image size for CSS printing

Personal as I do to generate an image that has stayed in a div background with a text overlapping it and at the time I print it keep its size. Type I have an image generated in Photoshop with the following dimensions: 1024px by 749px with 200 dpi this would give 13x9.5 cms real. So when I put it in the html and ask to print it it gets the full width of the 20cms page. I'm using the following CSS for this div:

#div{
     width: 1024px;
     height: 749px;
     background: url(cartao.jpg) no-repeat !important;
     margin-bottom: 20px;
}