That picture is gold. I love how Newt is just constantly red in the face in that pic.

I imagine there's a secret community of aurors in the department that just circulate their drawings amongst themselves until one of the more clumsy and absentminded amongst them leaves their latest masterpiece lying around.

Or, Tina and Queenie are the ones actually drawing these pictures and they've ended up gathering a following. A secret following. Queenie seems like the one who'd leave these pictures on Graves desk whenever Newt comes to visit. It's all part of her plan to get them together.