A Tewksbury High School student was arrested and charged this week after he posted a picture of another student using the bathroom on social media, the Middlesex District Attorney’s Office said. Jason Dipremio, 18, of Tewksbury is accused of taking an inappropriate photo of a 15-year-old student while he was using the bathroom at the high school at about 1 p.m. Wednesday and sharing it on Snapchat. Tewksbury High officials said the incident was brought to their attention by other students. Dipremio was charged with photographing a minor in a state of nudity and disseminating a photo of a minor in a state of nudity in Lowell District Court. He was held on $500 bail. He will return to court Aug. 4.In addition to criminal charges, Tewksbury High School said Dipremio violated the “acceptable use policy of the school district and in doing so, has used technology in a way that violated student privacy rights,” according to a letter to the school community from Principal Jon C. Bernard. The school said it’s working with police in the ongoing investigation.