Four West Side aldermen are firing back at the Civic Federation president for daring to question Mayor Rahm Emanuel’s decision to sell off a valuable painting and use the $15 million-plus in proceeds to give the West Side a regional library.

In a letter to Civic Federation President Laurence Msall, aldermen Michael Scott Jr. (24th), Walter Burnett (27th), Jason Ervin (28th) and Emma Mitts (37th) said they have a “better pulse” on what the West Side needs than Msall does.

“Every time a new investment is coming to the West Side, critics from other parts of the city’s can’t wait to shoot it down and tell us what’s best for our neighborhoods,” the letter states in an apparent reference to the furor over a new $95 million police academy in West Garfield Park.

RELATED: Artist Key James Marshall slams Chicago’s plan to sell his painting

“Here’s something you may not know: We have not had a regional library with weekend hours on the West Side in over 40 years. That’s two generations of children who grew up in our neighborhoods without the same amenities families everywhere else in the city take for granted.”

Emanuel wants to restore the Legler branch library, 115 S. Pulaski, to the regional status it held until the 1970’s.

That would require the city to spend an estimated $11.2 million to expand the 36,000-square-foot library and another $1.7 million-a-year to expand its programming and operating hours to match the city’s two other regional libraries.

To do that, Emanuel has made what Cultural Affairs and Special Events Commissioner Mark Kelly called the “difficult” decision to sell off “Knowledge and Wonder,” a large painting by renowned artist Kerry James Marshall that hangs on the second floor of the Legler branch.

To appease public art aficionados, Emanuel would create a public art fund to support art projects in under-served communities.

The sale will be handled by Christie’s Auction House. City Hall is counting on it to generate upwards of $15 million.

None of that sits well with Msall. That’s because it’s “not tied to an operating plan.”

But the letter from West Side aldermen, obtained by the Chicago Sun-Times, essentially tells the Civic Federation president to butt out.

“What we do not appreciate and will not countenance is when people who do not live in our communities, work in our communities or raise families in our communities think they know what is best for our communities,” the letter states.

As a regional library, Legler will be open six-days-a-week and finally feature a state-of-the-art computer center as well as a community center that will help West Side residents “connect with job opportunities and city services,” the letter states.

“Chicagoans in other communities already enjoy access to these amenities. A new regional library in West Garfield Park will help put an end to this decades-old disparity and right an historic wrong,” the aldermen wrote, calling the project a “significant down-payment on a more equitable future” for Chicago.

Msall is not the only one voicing concerns about the controversial sale of the valuable work of art.

So is the artist himself, Kerry James Marshall.

A story in ARTnews quoted Marshall as saying, “I am certain they could get more money if they sold the Picasso sculpture in Daley Plaza.”

During the London interview, Marshall was further quoted as saying, “Considering that only last year Mayor Emanuel and Commissioner Kelly dedicated another mural I designed downtown for which I was asked to accept one dollar, you could say the City of Big Shoulders has wrung every bit of value they could from the fruits of my labor.”

That was an apparent reference to a mural he painted at the Chicago Cultural Center. Marshall spoke at the dedication in December.