Most in-store photo processors (CVS, Walmart, etc.) will take a photo of you and give you 2 passport photos. If you don’t need extra photos, this way is the safest way of getting photos that meet government requirements. When traveling internationally, it is always a good idea to have extra passport photos. Not only do some countries require the photos for visas, some parks (like Angkor Wat) also require a passport photo to include on your ticket.The quickest and easiest way to do it yourself is to use a free service like ePassportPhoto. ePassportPhoto gives you simple instructions to take, upload, and a simple tool size your photo online. You then download a 4×6 image that has 5 copies of your picture properly sized. Simply print this photo on your home printer or send to a service like CVS. 20 copies cost me $2. ePassportPhoto offers a $7 paid service were they will confirm your photo meets government regulations and sends you the photos in the mail. That service is probably worth the piece of mind if you are using the photo for your passport.
Note – different countries have different size regulations and ePassportPhoto will adjust for the country you need to comply with. This is something that CVS or Walmart don’t seem to offer.