The move by a judge in Nanterre on Thursday came after the national assembly voted in November to strip Le Pen of her parliamentary immunity over the three photos posted in 2015.
Le Pen, who lost to Emmanuel Macron in last year’s presidential vote, is facing charges of circulating “violent messages that incite terrorism or pornography or seriously harm human dignity”, and that can be viewed by a minor. The crime is punishable by up to three years in prison and a fine of €75,000 (£66,000).
The pictures were posted a few weeks after the Paris terror attacks in November 2015, in which 130 people were killed.
One of the images showed the body of James Foley, an American journalist beheaded by Isis extremists. The others showed a man in an orange jumpsuit being driven over by a tank and another man being burned alive in a cage.
“Daesh is this!” Le Pen wrote in a caption, using an Arabic acronym for Isis, in response to a TV journalist drawing a comparison between the extremists and the French far right.
Le Pen later deleted the picture of Foley after a request from his family, saying she had been unaware of his identity. “I am being charged for having condemned the horrors of Daesh,” Le Pen told the news agency AFP. “In other countries this would have earned me a medal.”
In September, parliament lifted the immunity of another Front National MP, Gilbert Collard, over similar tweets containing Isis images.