Timothy Moule, a senior teacher at schools in Wolverhampton and Telford, was also a lead in safeguarding, a court heard.
Mr Howard Searle, prosecuting, said the 47-year-old, of Severn Way, Cressage, near Shrewsbury, committed offences of voyeurism and amassed more than 3,000 indecent images over an 11-year period.
Moule was arrested in April last year following a police inquiry into inappropriate contact with a teenage boy which fell short of criminal behaviour.
His laptop and hard drives were seized and police found the indecent images, which had been downloaded following 1,700 separate paedophile-related web searches.
Mr Searle said police also recovered several videos of children changing from their school uniform into their sports kit, which Moule had secretly filmed on a number of occasions.
He told Stafford Crown Court that Moule had admitted downloading the indecent images but denied they gave him sexual gratification.
The images ranged from category A, the most serious, to C, and the ages of the children involved ranged from two to 11.
The court heard that they were seen to be in pain and distress.
Moule, who is married, pleaded guilty to six charges of voyeurism and two of possessing indecent images.
He had initially denied the charges.
Mr Jasvir Mann, representing Moule, said: “He knows there cannot be any excuses for his behaviour.”
Moule was jailed for 33 months for voyeurism and an additional 19 months for being in possession of indecent photographs of children.
Jeanette Bryant, Senior Crown Prosecutor with the West Midlands Crown Prosecution Service’s Rape and Serious Sexual Offences Unit, said today: “Through his career as a teacher, Tim Moule would have been fully aware of the school’s safeguarding guidelines, yet he chose to ignore these policies and contacted his students via social media.
“He continued to abuse his position of trust and authority by covertly filming a number of students, who were under the age of 13.
“The defendant admitted to voyeurism and taking indecent photographs of a child, and he will now have to deal with the consequences of his actions.”