Educational institutions do not need consent from parents to process children’s data as long as the school is processing data to perform its duties.  Educational institutions, e.g. public schools, are processing children’s data as official authorities, and their legal premise would therefore not be consent, but article 6(1)(e). The school will need to ask for consent if they want to use the child’s data for advertising purposes, e.g. sharing its picture on the school’s website.