Fixed JPG saving through converting INT_ARGB to INT_RGB.
Previously, JPGs ended up being saved as four channel CMYKs.  Now,
conversion goes through drawing the INT_ARGB image into an INT_RGB image
which feels wasteful.  In addition, the signature of the Utils method
changed to accept BufferedImage instead of RenderedImage which I do not
like much either.  A better solution would be highly appreciated.