have seen a steep decline in the past 20 years as royalty free licenses have become the preferred model for clip art. Public domain images continue to be one of the most popular types of clip art because the image rights are free. However, many images are erroneously described as part of the public domain are actually copyrighted, and thus illegal to use without proper permissions. The main cause for this confusion is because once a public domain image is redrawn or edited in any way, it becomes a brand new image which is copyrightable by the editor. The United States District Court ruled in 1999 as part of Bridgeman Art Library v. Corel Corp that exact copies of public domain images were not restricted under US copyright law, however the scope of this ruling only applies to photographs currently. It is originality,not skill, neither experience nor effort, which affects copyrightability of derivative images. In fact, the US Supreme Court in Feist v. Rural ruled that the difficulty of labor and expenses must be rejected as considerations in copyrightability. Copyright on other clipart stands in contrast to exact replica photographs of paintings. The large clip art libraries produced by Dover Publications or the University of South Florida's Clipart ETC project are based on public domain images, but because they have been scanned and edited by hand, they are now derivative works and copyrighted, subject to very specific usage policies. In order for a clip art image based on a public domain source to be truly in the public domain, the proper rights must be granted by the individual or organization which digitized and edited the original source of the image. The popularity of the Web has facilitated widespread copying of pirated clip art which is then sold or given away as "free clip art". Virtually all images published after January 1, 1923 still have copyright protection under the laws of most countries. Images published prior to 1923 need to be carefully researched to make sure they are in the public domain. Creative Commons licenses is the forefront of the copyleft movement or a new form of free digital clipart and photo image distribution. Many websites such as Flickr and Interartcenter use Creative Commons as an alternative to the full attribution copyrights. The exception for clip art illustrations created after 1923 are those which are specifically donated to the public domain