Interesting app so far, I especially like the photo part, because people often are misidentified based on what's in their wallet. I just noticed a few minor ways the app could be improved from a medical perspective. First, it's dangerous to default to "None" for allergies, as there's little way to tell if someone doesn't have any or didn't enter any (and an ER doc is prone to copy that "None" into the medical record, and other doctors are unlikely to ask again). Also, for allergies, it's more useful to have a list containing the drug and what the reaction was. The difference between a side effect, adverse reaction, and allergy are difficult for people to understand, so the nature of the reaction tells medical people what really happened.
For example, if someone is having a heart attack and they list "Contrast dye allergy" then there are two very different possibilities. One is an anaphylactoid reaction where they go into shock and respiratory failure (true allergy). Another is renal failure (an adverse reaction due to known nephrotoxicity). The management of the two is quite different, and both have harm that can be somewhat mitigated if it's known beforehand.
Additionally, other useful information would be current medications (Name, Dose, Frequency, Route, and how long you've been on it), and the name/address of one's primary care doctor and others with medical records on you. Past surgical history (e.g. clean cath in 2010, appendectomy in 1990) also saves time. More identification and insurance information might also be useful, albeit irrelevant for emergency medical care (helps with getting records though).
All that said, in all likelihood, EMS or an ER doctor won't spend more than a minute or so skimming the information so everything has to be concise and obvious in how to use. Plus, most medical emergencies are managed the same way initially, so a lot of this information comes into play later, when most people are responsive (unless it's really bad, like head trauma after a car accident). Speaking of which, you may consider adding some vague living will type information for guidance, albeit something legally binding is beyond the scope of such an app.
