She did it to object to views voiced by an author, who said there were similarities between her party and Islamic State.
"This is #Daesh," she said in the posting, using the Arabic term for the jihadist group that controls swathes of Syria and Iraq and is being bombed by western forces.
The beheaded corpse of a man in a prisoner-style orange tracksuit with his severed head placed on his chest was among the photos.
"We are offended that that awful image of our son`s brutal murder be used publicly," Diana Foley said in an interview on Europe 1 radio.
"To tweet it again just continues to promote their propaganda - the horrible way they recruit others who want to be brutal. I certainly do not want that to continue."
Separately, in a joint statement with Foley`s father John tweeted by Nicolas Henin, a French journalist and former Islamic State captive, Diana Foley said: "We are deeply disturbed by the unsolicited use of Jim for Le Pen`s political gain and hope that the picture of our son, along with two other graphic photographs, are taken down immediately."
A spokesman for the National Front had no immediate comment on Diana Foley`s remarks.
The beheading picture was no longer showing on Le Pen`s Twitter account on Thursday, but two others - one showing a prisoner being burnt alive and the other a tank driving over another man in an orange tracksuit - were still there.
Le Pen`s tweet was a response to a comment from Gilles Kepel, an academic who this week published a book called `Terror in the Hexagon (France)` about French-born jihadis.
In a radio interview, Kepel said that although Islamic State and the FN were very different, there were similarities because of their politics of exclusion.
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