on the right is a bookend that was being sold by a store in San Francisco, Koons sent them a cease and desist letter, saying we've got to stop selling this, this is derivative of my work,they said no we're not going to stop and he wisely back down because he basically had appropriated a folk art form,that had been going on for decades before he created sculpture,I think would be very difficult for Koons to present that this was his intellectual property.

2⃣️sculpture string of puppies:it is a photograph by art Rogers which had been printed as a postcard which Jeff Koons bought in a souvenir stand and used as the source material for the sculpture.

2⃣️Niagara feet:the second pair of feet is from the left was taken from a photograph that had been published in Allure magazine, so the photographer sue Jeff Koons over copyright infringement ,

it's now considered one of the most important works of the 20th century and that's because Duchamp was saying the artist can make a very minimal gesture basically just selecting something and transform it into a work of art.

that was incredibly radical at the time and it's something that I think that the laws still have trouble kind of addressing in contemporary society .

sheery levine2⃣️is a photograph by Walker Evans, sherry Levine rephotographed this image and a number of other photographs by Evans and presented them as her own work After Walker Evans

1⃣️mona lisa which within the domain name:which I don't know if Andy Warhol can claim copyright on this image but if so,it would not expire until 2057

Andy Warhol created the works based on copyrighted material from other artists, so this is not a photograph of Marilyn Monroe that Andy Warhol took himself, it's something that he found in a newspaper or magazine created a silkscreen and made a series of paintings

the flower: he made them in a number of different sizes and in hundreds of different color combinations and he did this using a silk screen like the Marilyn Monroe images and many of his paintings during this period not based on a photograph that Warhol took himself it was something that he found in a magazine,

now the original photograph was actually rectangular, it had 7 flowers so he cropped it, he made some little alterations to the flowers themselves but the original photographer came across the paintings ,she brought a lawsuit against Andy Warhol ,

so despite the fact that you bought that Warhol painting and spent 1.2 million dollars you do not have the right put it on a t-shirt or a tote bag or jigsaw puzzle

so despite the fact that Andy Warhol has been dead for 20 years more or less, his estate still maintains the copyright on any work that he made .

you get the canvas which lawyer called real proeprty, and what you wont own is the IPRs

if we look at the history of art in the 20th century, a lot of the most important works incorporate copyrighted material, and I think most of the art historians would agree those are important pieces that changed the course of art history and vital works.

it's very difficult if you're an artist working with appropriated imagery to know whether you're on the right side of the law or on the wrong side,

that's something that was incredibly radical at the time and the laws still have trouble kind of addressing in contemporary society.

however, the question of ownership I think comes up again and again (especially in postmodern art ).