How do you get art in animal crossing lets go to the city

the only way to get art is to go to the city and go to Redd's shop. he will have paintings in his shop. but be careful! they are very high prices and some are even fake!
the way i know if they're fake is if the name of the painting ends in the word 'painting'. i.e - 'amazing painting' or 'wonderful painting', are both fake.