I found a , and of the photo of Hannah as Agnes with her 'new mother' (can't quite bring myself to call her Agnes or the women her mother as Hannah has been stolen.)
I think it does show Hannah with her new parents now. The colour of the dress looked more red than pink on my TV but on the laptop it looks pink and the figure is smaller than the two adult figures. So I've changed my mind, what I thought was a handmaid is actually Hannah in the drawing.
Just a thought. When Serena took June to see Hannah before, and made her threat, that was at a different house.
So it could be the MacKenzie family country home and city home. And they trusted Serena enough to let her see Hannah and bring her outside.
The Waterford's have had access to Hannah before, either though the parents or through the Martha and guard / driver. They've visited her, got photo's of her, and arranged to have her brought to the country house.
Serena felt comfortable to walk into the house screaming Offred while Fred was more cautious in calling for Commander MacKenzie.
Serena seemed to be convinced the house would be empty and certainly not expecting the family to be in it. Fred seemed more cautious but questioning. He wasn't expecting Commander MacKenzie to be there but he wasn't sure.