The large painting The Battle of Alexander at Issus is a 1529 oil painting by the German artist Albrecht Altdorfer. I saw it the last time I went to Munich and took a picture. Fast forward a few years and I got a puzzle of it out of the blue-random find at Half Price Books. I recognized it and looked through my old photos I took at museums, and it turns out I had indeed seen it and it was one of a few pictures I took at that particular museum. Nifty.