The well-known picture of King David playing a triple harp, by Italian painter, architect and harp-builder Domenico Zampieri (1581-1641). You can click on the image to get a bigger picture. The colour in the larger image isn’t quite as good, but it does show more detail, including a bit more of the top of the painting, and you can see the strings on the harp more clearly.
A number of harp-makers have made replicas based on this painting. Since Zampieri was himself a harp-builder, one might assume that the harp is accurately represented. However, having King David play a triple harp of this sort is, according to Roslyn Blyn-Ladrew, “an anachronistic error by Zampieri of over 2000 years”. You can see Ms. Blyn-Ladrew’s full article here.