I just bought a puzzle with this picture on it, it's "The Druids - Bringing in the Mistletoe" by E. A. Hornel and George Henry. Hornel and Henry were part of the Glasgow (Scotland) art movement of the late 1900s. This piece is a collaboration between the two of them. The colors and composition are what struck me the most, I also like the fact that parts of it become painterly and abstract (which will make interesting puzzling). If anyone is interested I'll post the 1000-piece final product!