After upgrading this morning
Fatal Error: Cannot make static method GKIS_Image::createThumbnail() non static in class GKIS_Startup_Image in .../modules/mod_image_show_gk4/styles/gk_startup/class.image.php on line 126
If I unpublish the module I have the site back without the header show.
I'm on Joomla 3.5 on php 5.4.39
Any ideas?