replace getImage() into getImageFileName() (fixes #2698)
replace getImage() into getImageFileName() (fixes #2698)

nishizoe/OpenPNE3,upsilon/travis-test,upsilon/travis-test,ShinichiU/OpenPNE3,ShinichiU/OpenPNE3,nishizoe/OpenPNE3,C-nakajima/OpenPNE3,C-nakajima/OpenPNE3,ShinichiU/OpenPNE3,kashiwasan/symfony-advanced,isaosano/OpenPNE3,isaosano/OpenPNE3,isaosano/OpenPNE3,C-nakajima/OpenPNE3,ShinichiU/OpenPNE3,isaosano/OpenPNE3,C-nakajima/OpenPNE3,kashiwasan/symfony-advanced