No matter how long the portrait has been on display and no matter how many people want it there, the U.S. Constitution mandates a separation of religion and government.
MORE: https://www.au.org/blogs/wall-of-separation/picture-imperfect-ohio-school-district-defies-request-to-remove-portrait-of
See also...
Jesus Portrait to Stay at Ohio School Defying Atheist Demands
http://www.christianpost.com/news/jesus-portrait-to-stay-at-ohio-school-defying-atheist-demands-88147/
