Also if you print using a borderless option, so that you completely fill the length of the paper, even with a white strip top and bottom you will lose something like 60 pixels form each "end" of the image (at least its about 60 if the image is resampled to fill the image size at the same PPI value the printer is using). This is done to stop any unprinted bits from showing around the edges cause by tolerance issues within the printer, and the paper not always feeding exactly square. The only way around that is to chose a normal, not borderless printing option. This will print all the pixels around the edge of the image, but will of course mean that you will have a certain amount of white border around the image.
This is in addition to the aspect ratio issues that Elei mentioned in his post above.