image: fix warnings with coming 1.32 glib
image: fix warnings with coming 1.32 glib

pwithnall/mx,jonnylamb/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx,jonnylamb/mx,pwithnall/mx,pwithnall/mx,jonnylamb/mx,clutter-project/mx,clutter-project/mx,clutter-project/mx