There's only one thing a profile pic needs to do: reliably signal that this is the specific person of that name that people are looking for. A reasonably well-

There's only one thing a profile pic needs to do: reliably signal that this is the specific person of that name that people are looking for. A reasonably well-lit picture of your face will serve admirably. Serious or happy or amused are good expressions; try not to look angry or sad. There, you're done.