This image is a carte de visite or CdV. The girl pictured has a lovely round face and an uncertain expression on her face, and she looks an awful lot like my own 3-year-old daughter. I’d guess this child is a little bit younger because she still has so much baby fat in her face. We can safely date the picture from 1864-1869 because 1) the square corners of the card and 2) the border style. According to Photo Tree these factors were popular in the mid to late 1860s. Because I will be at a Civil War reenactment this weekend, I thought this an appropriate image to feature.
I do wonder who this beautiful girl was.