Méliès is technologically and technically resourceful, as well as being sensitive to the direction, the need of the story. That’s why we find him here, adjusting shot size for dramatic purpose.
It turns out he’s a very good speed drawer. In his essential study of the silent film comedy (1975), Walter Kerr observed that the Chaplin character was reliably, strikingly, almost miraculously adaptable. It seemed that he could master any task, surmount any challenge with amazing alacrity. Not only did he manage, but he actually excelled. This superhuman ability actually made it difficult, even impossible, to ever fully settle, or belong.
That last part is not pertinent to the present discussion. (I just wanted to give a sense of Kerr’s idea, and its convincing conclusion.) But as a filmmaker, Méliès is pretty Chaplin-like, isn’t he? He can do anything! In addition to the drawing we can see that he is using a trick dissolve, instead of his usual trick cut. Different but same, you might say. But if you want to think about it in a different way, he’s also inventing the effect, right before our eyes, that makes the Jekyll and Hyde transformation possible. (As in John Barrymore and Jerry Lewis, not Fredric March and Spencer Tracy.)