How to remove decal? Logo?

Accidentally drag and dropped an image file onto an assembly window.  Cannot find a way to get rid of it, undo is no longer an option.  Have already removed all appearances, which worked until I re opened the file.  Ive looked at logos, decals, at top level and part levels, cannot find where this image file is referenced.  HELP! 

Thanks

SolidworksModeling And Assemblies