Album art on the English wikipedia is under the fair-use licence, meaning that it is not free. If the country you plan to use the artwork in supports fair use than you can use it. If not you can't.
Yes, it is legal, but only if you get it from Google. (its the safest one)
"The cover art was made by Dan Mumford." said wikipedia
yes,lime wire
Naïve Art - album - was created in 1989.
The Art Garfunkel Album was created in 1973.
Art Vandelay - album - was created in 2011.
Rock Art - album - was created in 1994-07.
The Art of Dying - album - was created on 2004-05-04.
The Art of Drowning - album - was created on 2000-09-19.
Watermark - Art Garfunkel album - was created in 1977.
The Art of Love - album - was created on 2007-05-31.
The Art of Self Defense - album - was created in 2002.