Ariel Winter's Mom -- Threatens to Sue Publicist Over Nude Photos Claim

Ariel Winter's mother, Chrystal Workman, has fired off a cease and desist letter to the publicist who claimed Chrystal demanded he leak nude photos of her eldest daughter -- however she does admit sending him scantily clad pics.

TMZ obtained a copy of the letter sent to Jonathan Hay ... in which Chrystal's attorney warns him to stop "making false and defamatory statements" because, "Ms. Workman never represented to Mr. Hay that nude pictures existed of her daughter Shanelle."

But in the same letter Workman admits sending Hay 2 photos of Shanelle Gray, which she says she found on the Internet -- and while they're not fully nude ... they are very revealing.

But it turns out the photos were NOT private or secret in any way ... they were taken at a cast party for "One Life to Live" by a professional photographer. FYI -- Shanelle was in the cast when the pics were taken.

In the cease and desist letter Workman's attorney says, "The attached email contains pictures which raise the question, to Ms. Workman, whether Shanelle is fit to be the guardian of a teenager."

As we previously reported, Hay had claimed Ariel's mother sent him nude photos which she wanted leaked to the public -- presumably to smear Shanelle ... who's taken guardianship of Ariel in the wake of allegations Chrystal was abusing the "Modern Family" star.

Hay has responded to Chrystal's letter with a letter of his own in which he claims Chrystal herself "described these photos to me as 'nude photos' before I even saw them." He also points out the photos "expose intimate parts of [Shanelle's] body."