The painting by Kara Walker, a renowned African-American artist, was placed in the library the week of Thanksgiving, The (Newark, N.J.) Star Ledger reported.
The painting depicts the horrors of reconstruction, 20th century Jim Crow conditions and the hooded figures of the Ku Klux Klan, as well as a white man holding the head of a naked black woman to his groin.
Library employees requested the painting be taken down. Library director Wilma Grey didn't see a problem with the artwork but covered it with fabric until the matter could be discussed.
The fabric was removed after the library explained why it supports the painting.
"The library should be a safe harbor for controversies of all types, and those controversies can be dealt with in the context of what is known about art, about literature, democracy and freedom," said Clement A. Price, a library trustee and Rutgers history professor. "There's no better venue in Newark where such a powerful and potential controversial drawing should be mounted."