This resizing does bad things to image quality, especially if the image you are sending to the printer is a JPG because JPGs will not maintain the pixel integrity of your image as well as a PNG file type will. If you send too many it has to shrink the image smaller.
If you send too few pixels to the printer it will just make pixels up in an effort to fill the page. To get the best resolution when printing, you need to signal to your printer how many pixels per inch (PPI) you want it to print. Here are some guidelines for getting the best quality prints from your photos: Start with the right size and shape
