bootstrap.image: allow making other images in main.
bootstrap.image: allow making other images in main.

factor/factor,mrjbq7/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,factor/factor,bpollack/factor,tgunr/factor,bpollack/factor,factor/factor,tgunr/factor,bpollack/factor,bpollack/factor,tgunr/factor,bpollack/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,factor/factor,bpollack/factor,bpollack/factor,mrjbq7/factor,factor/factor,tgunr/factor,mrjbq7/factor