To what extent do visual concepts of dogs, cars, and clocks change across childhood? We hypothesized that as children progressively learn which features best distinguish visual concepts from one another, they also improve their ability to connect this knowledge with external representations. To examine this possibility, we investigated developmental changes in children's ability to produce and recognize drawings of common object categories. First, we recruited children aged 2-10 years to produce drawings of 48 categories via a free-standing kiosk in a children's museum, and we measured how recognizable these >37K drawings were using a deep convolutional neural network model of object recognition. Second, we recruited other children across the same age range to identify the drawn category in a subset of these drawings via "guessing games" at the same kiosk.We found consistent developmental gains in both children's ability to include diagnostic visual features in their drawings and in children's ability to use these features when recognizing other children's drawings. Our results suggest that children's ability to connect internal and external representations of visual concepts improves gradually across childhood and imply that developmental trajectories of visual concept learning may be more protracted than previously thought.