10/8    I have a couple png images (blue on a white background) for which I'd
        like to have a transparent background (instead of white).  Is there an
        easy (ie, not erasing each pixel) way in gimp2 to do this?  The whole
        image is just one layer.  Thanks.
        \_ Select all of one color (blue).  Copy. Open new document with
           background specified as transparent. Paste. Save. All right, so this
           is really Photoshop specific, but surely there are analogues in
           Gimp 2?