As adjectives the difference between picturesque and postcardlike
is that picturesque
is resembling or worthy of a picture or painting; having the qualities of a picture or painting scenic while postcardlike
is resembling a postcard or some aspect of one; picturesque.
As a noun postcard
is a rectangular piece of thick paper or thin cardboard intended to be written on and mailed without an envelope in the case of a picture postcard one side carries a picture or photograph.
As an adjective postcardlike is
resembling a postcard or some aspect of one; picturesque.