Urban Milano Italy Street art / Mona Lisa Long Sleeve T Shirt

I love the art on the shirt, it is wonderful and creative. The problem with the shirt was I ordered a large but it was huge!!! Then I ordered the small and it was a small. Want to get another for my mom but worried that the medium will also not be the right size. Help!! I ordered the long sleeve gray with the woman's pic but that large would not even fit a huge guy!!!