Annie Leibovitz regularly contributes to Vanity Fair magazine
Celebrity photographer Annie Leibovitz is being sued over a $24m (£14.5m) loan secured against the rights to her entire collection and her properties.
The Art Capital Group (ACG) is asking a judge to force her to give real estate agents access to her New York homes so they can be sold off to repay the loan.
The breach of contract suit also seeks her co-operation on selling off her copyrights to help with repayment.
Her spokesman denied the allegations, accusing ACG of "continued harassment".
Ms Leibovitz, the action claims, is guilty of "boldly deceptive conduct".
But her spokesman said in a statement: "There has been tension and dispute since the beginning.
"For now, her attention remains on her photography and on continuing to organise her finances."
Ms Leibovitz's reported financial difficulties led her to seek a $22m (£13.3m) loan from a division of ACG.
That amount, subsequently increased to $24m, was secured against the rights to all her photos and her properties.
First Lady Michelle Obama was one of Ms Leibovitz's recent subjects
In documents, filed in New York State Supreme Court on Wednesday, the group claims that Ms Leibovitz "acknowledged her fine art, intellectual property and real estate assets would likely need to be sold" as part of her financial restructuring.
Ms Leibovitz, 59, is one of the world's most famous photographers, having photographed subjects including a pregnant Demi Moore and US First Lady Michelle Obama.
Last year, she became embroiled in controversy over a Vanity Fair photograph of Miley Cyrus that appeared to show the teen star topless.
She was also caught up in the row over BBC documentary Monarchy after a trailer misleadingly suggested the Queen had stormed out of a photo shoot with her at Buckingham Palace.
According to its website, ACG "offers financial and consulting services to assist art owners in creating liquidity from art assets".
According to the New York Times, American artist Julian Schnabel also took out a loan with the firm only to subsequently sue them for allegedly charging exorbitant fees.