How Do I Figure Out How Many MegaPixels Are Necessary for Printing a Photo at a Specific Size? [Ask Lifehacker]

How Do I Figure Out How Many MegaPixels Are Necessary for Printing a Photo at a Specific Size? [Ask Lifehacker]: "

Dear Lifehacker,
I have a camera that's capable of more megapixels than I can fathom, and I know I don't need photos at such a high resolution, but I do want to be able to at least print full page photos. How can I determine how many megapixels are necessary to print a photo at a given size? More »

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