However I did a google image search for Yoda’s lightsaber in ep. II & III and it looks just like the lightsaber in this painting. I also looked at pictures of Yoda from TPM, the original version, and I couldn’t see him carrying a lightsaber. So I guess this could have been made based on some early AOTC artwork, but until I find a specific date I’ll still be somewhat confused by this one.
IIRC, the TPM Visual Dictionary provided an image of Yoda’s lightsaber hilt.