No, I have no explanation for the photograph above. The only place that I have seen it is on Hyperdox Herman. However, see the photograph below from a post of mine from nearly four years ago.
Look at the chalice. I believe that it is the same one. As to whether this is the same occasion, I cannot tell. But, it does appear that these giant chalices get regular usage. I wonder what was the size of the original loaf of bread from which the center lamb was cut. The chalice could not be very heavy, notice that the subdeacon is holding it with one hand in the first photograph. Either he is very strong or the chalice walls are very thin.
I hope that this practice never catches on in the USA for massive celebrations!
My parish usually uses a lamb of approximately that size on Pascha, when we typically get well over a thousand communicants. Our largest chalice is much smaller, though; that night, the priest puts barely any water in the chalice at the proskomedie, and the Blood is ladled into four or five chalices (we have a lot of clergy) at “Holy Things are for the Holy” before the rest of the hot water is added.