Walgreen's has an advertised special of $0.10 per 4"x6" print if you buy 50 or more. I was planning on having about 300 photos printed out. My question arises from the DPI tags on the photos. Just about half have an image dpi of 72, while the rest are 300 dpi. Do I need to go into photoshop and change the tags on the 72 dpi photos to 300 dpi? Since there is no batch function that allows me to change the print size without resampling the image it will take quite a bit of time to modify 150 photos individually. The photos all have a resolution of 4,288 x 2,848. So that leads to my question, will there be a difference in quality or any difference between the photos tagged at 72 dpi vs those tagged at 300 dpi?