Gautham, doing his fourth year in a private college here, was in love with a girl and had visited many places and taken photos with her in the last few months, police said.
He reportedly sought Rs one lakh from the girl and threatened to upload her pictures on the site when she refused, they said.
To teach her lesson, he posted her picture on a site, following which the girl filed a complaint with the cyber crime wing, which took him into custody a few days ago but he was released after a warning was issued, considering his education career, police said.
Based on the complaint, police arrested him last night and registered cases under various sections, including Prevention of Harassment of Women's Act.
He was remanded to custody and lodged in the central prison here.