A caller who said he was angry at his girlfriend for posting nude photos of him online threatened to blow up a Queens prep school Tuesday, causing the building’s evacuation, cops said.

The suspect called St. Francis Preparatory School in Fresh Meadows at 11:23 a.m. and threatened to set off pipe bombs at 1:30 p.m. in the building at 6100 Francis Lewis Blvd., according to police.

The caller said he was mad at his girlfriend because she had posted nude photos of him online, police said.

It’s not clear what connection the caller or girl had to the school.

Calls to the school were not answered in the afternoon.