You have your driver's license photo taken at the DMV office. When you take your photo, you should make sure that you wear what you would normally wear, and it's important that your face is recognizable.
Typically, you will need to bring proof of your identity, proof of your legal presence in the United States and proof of your residency in Virginia. If you have been issued a Social Security Number you will have to provide proof of that as well. The VA DMV website has more information about what documents you should bring with you. Visit here http://www.dmv.virginia.gov/apps/documentbuilder/intro.aspx