But the simple camera phone is epochal in that it puts the power—literally—into the hands of patients. The photographic possibilities extend far beyond the skin. In the pediatric gastroenterology clinic, many concerned parents bring in photos of their kids’ dirty diapers, which all parties agree is vastly preferable to bringing in the real thing. Some neurologists recommend that parents make videos of children who have a known history of seizures to help the team fine-tune medication doses. In developmental and behavioral clinics, parents can show videos of their children at home demonstrating milestones like a mature pincer grasp or pulling to stand, even if the kids get shy about showing off their skills to a room full of doctors.

With regard to taking photographs or videos of patients, health-care providers are bound by the privacy rules of the Health Insurance Portability and Accountability Act. But parents are free to capture such pictures. Especially in pediatrics, parents are encouraged to be advocates, and phones can be their close allies.

But even at its best, a snapshot cannot replace a thorough history and physical examination. Had the mother of the 15-month-old patient with roseola told me a different story, the photo she showed me could have been the rash of contagious measles. Instead of expecting a picture to replace a thousand words, we should take the more prudent step of welcoming this new tool into the ever-growing digital inventory available in the fight against disease.