The Syrian Observatory for Human Rights said "warplanes - either Russia or Syrian - carried out six strikes" in the village of Hass, including on a school complex.
The raids hit the village around 11:30 am (0830 GMT), an activist with the opposition Idlib Media Centre told AFP.
"One rocket hit the entrance of the school as students were leaving to go home, after the school administration decided to end classes for the day because of the raids," the activist said, speaking on condition of anonymity.
The authenticity of the picture could not be independently verified.
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The Observatory, a Britain-based monitor of Syria's five-year conflict, initially reported two schools had been hit but later clarified that it was a school complex made up of multiple buildings.
Idlib province is controlled by the Army of Conquest, an alliance of rebel groups and jihadists including the Fateh al-Sham Front, which changed its name from Al-Nusra Front after breaking off ties with Al-Qaeda earlier this year.
Syrian government forces and their Russian ally have been criticised by rights groups for indiscriminate attacks on civilian infrastructure.
More than 300,000 people have been killed since Syria's conflict erupted in March 2011.