'Return a list of image objects. If no project is specified, a list of
all non-deprecated global and vendor images images is returned. By
default, only non-deprecated images are returned.
:keyword  ex_project: Optional alternate project name.
:type     ex_project: ``str``, ``list`` of ``str``, or ``None``
:keyword  ex_include_deprecated: If True, even DEPRECATED images will
be returned.
:type     ex_include_deprecated: ``bool``
:return:  List of GCENodeImage objects
:rtype:   ``list`` of :class:`GCENodeImage`'

def list_images(self, ex_project=None, ex_include_deprecated=False):

    dep = ex_include_deprecated
    if (ex_project is not None):
        return self.ex_list_project_images(ex_project=ex_project, ex_include_deprecated=dep)
    image_list = self.ex_list_project_images(ex_project=None, ex_include_deprecated=dep)
    for img_proj in list(self.IMAGE_PROJECTS.keys()):
        try:
            image_list.extend(self.ex_list_project_images(ex_project=img_proj, ex_include_deprecated=dep))
        except:
            pass
    return image_list
