def section_keyword(bounds, flipx=False, flipy=False):
    """Package image bounds as a NOAO image section keyword value."""
    xmin, xmax = bounds.xmin, bounds.xmax
    ymin, ymax = bounds.ymin, bounds.ymax
    if flipx:
        xmin, xmax = xmax, xmin
    if flipy:
        ymin, ymax = ymax, ymin
    return '[%i:%i,%i:%i]' % (xmin, xmax, ymin, ymax)