From Wikipedia:
Joan Miró was remembered by the Google corporation on their website
http://www.google.com. Artwork and elements of several works by the Spanish surrealist incorporated into Google's logo on Thursday, April 20, 2006 memoralizing his fame and artistic aptitute. On Thursday morning, the family of Joan Miro was upset to discover this and The Artists Rights Society, a group that represents the Miro family and more than 40,000 visual artists and their estates, asked Google to remove the image early Thursday morning.[2]
``There are underlying copyrights to the works of Miro, and they are putting it up without having the rights, said Theodore Feder, president of Artists Rights Society.[2]
In a written statement to the Mercury News, Google said that it would honor the request but that it did not believe its logo was a copyright violation.[2]Approximately 5:00 pm, Google corporation removed the Joan Miro Google logo, and replaced it with its standard logo.