Molly Brett (1902–1990)  was an English illustrator who has made many anthropomorphic illustrations, looking thoroughly naturalistic while using subtle colours and giving her drawings often a magical atmosphere. The title of this postcard is “Going shopping”, and shows a forest scene.
In the lower left-hand corner, a frog is walking with a land snail on a leash. The snail is stylised, with a humanised face and its shell is sinistral. It is, of course, an imaginary species.
Thanks to Joke van de Ouderaa for sending in this postcard.