Vicki, have you asked at the School? They may have one or know someone who does. Are you on friends reunited? You could try looking for the School on there and posting a message asking if anyone has photos. When I was looking for an old picture of a School I went to my local library and looked at newspaper archives around the year the School opened - I found some reports but unfortunately no pictures but you may have more luck. I also got in touch with the local council - sometimes they have pictures/plans which they will photocopy for you for a small fee.
When my daughter left School last year I told her to take her camera in on the last week and take photos of everything - the building, the corridors, classrooms etc.. she did but thought it was a stupid idea, however just this week she was looking through them with a friend and said she is grateful that I 'made' her do it. I know as the years go by she will be even more grateful to have them.
Good luck with your search.
Polly