Blender Git Commit Log

Image.gl_touch - routine to prevent the image to be cleared by blender cache garbage collection system
* if the image is not loaded (bindcode == 0) load the image

This needs to be called often. If the image is 'cleaned' by Blender, it will not help to load it after.
[ gl_load returns the errors: GL_STACK_OVERFLOW(1283) or GL_STACK_UNDERFLOW (1284) ]

Thanks Campbell for the suggestion on how to handle this (BKE_image_tag_time)