Authorities say 38-year-old Charles Coursey, of Milton, Del., and the student also sent text messages while at school.
Police say the text messages led to them meeting outside of school and engaging in a sexual relationship. Authorities say Coursey also sent obscene photos of himself to the student.
Coursey, who teaches at Sussex Tech High School, was charged Thursday with two counts of dealing in child pornography and two counts of obscenity.
He had already been charged with three counts of sexual abuse of child by a person of trust and four counts of unlawful sexual contact.
He is being held on $80,000 cash bail.
