Cover art is a type of artwork presented as an illustration or photograph on the outside of a published product such as a book (often on a dust jacket), magazine, newspaper (tabloid), comic book, video game (box art), DVD, CD, videotape, or music album (album art). The art has a primarily commercial function, for instance to promote the product it is displayed on, but can also have an aesthetic function, and may be artistically connected to the product, such as with art by the creator of the product.
Album cover art is artwork created for a music album. Notable album cover art includes Pink Floyd's The Dark Side of the Moon, King Crimson's In the Court of the Crimson King, the Beatles' Sgt. Pepper's Lonely Hearts Club Band, Abbey Road and their "White Album" among others. Albums can have cover art created by the musician, as with Joni Mitchell's Clouds, or by an associated musician, such as Bob Dylan's artwork for the cover of Music From Big Pink, by the Band, Dylan's backup band's first album. Artists known for their album cover art include Alex Steinweiss, an early pioneer in album cover art, Roger Dean, and the Hipgnosis studio. Some album art may cause controversy because of nudity, offending churches, trademark or others. There have been numerous books documenting album cover art, particularly rock and jazz album covers. Steinweiss was an art director and graphic designer who brought custom artwork to record album covers and invented the first packaging for long-playing records.
Whether printed on the dust jacket of a hardcover book, or on the cover of a paperback, book cover art has had books written on the subject. Numerous artists have become noted for their book cover art, including Richard M. Powers and Chip Kidd. In one of the most recognizable book covers in American literature, two sad female eyes (and bright red lips) adrift in the deep blue of a night sky, hover ominously above a skyline that glows like a carnival. Evocative of sorrow and excess, the haunting image has become so inextricably linked to The Great Gatsby that it still adorns the cover of F. Scott Fitzgerald's masterpiece 88 years after its debut. The iconic cover art was created by Spanish artist Francis Cugat. With the release of a big Hollywood movie, however, some printings of the book have abandoned the classic cover in favor of one that ties in more closely with the film.  
Today the word tabloid is used as a somewhat derogatory descriptor of a style of journalism, rather than its original intent as an indicator of half-broadsheet size. This tends to cloud the fact that the great tabloids were skilfully produced amalgams of intriguing human interest stories told with punchy brevity, a clarity drawn from the choice of simple but effective words and often with a healthy dose of wit. The gossipy tabloid scandal sheets, as we know them today, have been around since 1830. That's when Benjamin Day and James Gordon Bennett Sr., the respective publishers of The New York Sun and The New York Herald, launched what became known as the Penny Press (whose papers sold for one cent apiece). But some of the world's best journalism has been tabloid. From the days when John Pilger revealed the cold truth of Cambodia's Killing Fields in the Daily Mirror, to the stream of revelations that showed the hypocrisy of John Major's "back to basics" cabinet, award-winning writing in the tabloids is acknowledged every year at the National Press Awards. Good cover art can lead readers to this fact; the New York Herald, for example, offers some fine examples of tabloid cover art.  So too does the News & Review, a free weekly published in Reno, Nevada, Chico, California and Sacramento, California.  The tabloid has thrived since the 1970s, and even uses cartoonish cover art.  Tabloids have a modern role to play, and along with good cover art (and new ideas) they fill a niche.
Sheet music cover artists include Frederick S. Manning, William Austin Starmer, and Frederick Waite Starmer, all three of whom worked for Jerome H. Remick. Other prolific artists included Albert Wilfred Barbelle, André De Takacs, and Gene Buck.
Gentleman Jim Corbett and John L. Sullivan at Olympic Club, New Orleans
Album cover for The Beatles' "White Album", 1968
Book cover for Uezdnoe, by Yevgeny Zamyatin, 1916
Book cover for The Real Mother Goose, 1916, Blanche Fisher Wright, illustrator
Cover for (the) Billboard Magazine's tenth anniversary edition, 1904