Do not lose any image detail in your printed photos
Having a great looking image on your screen is one thing, but what people really want to see is a good looking print. Printers make images out of tiny dots. Most printers produce dots of a fized size which is determined by the printer’s resolution. When you send an image to the printer, the software usually resizes the image to match the printer’s DPI. The effect of the DPI on a print is the amount of detail in the printed photo. You may wish to change your image DPI to match the printer’s parameters. ImageConverter Plus will help you prepare a batch of images for printing.
http://www.imageconverterplus.com/help-center/solutions/process-images/change-image-dpi/