image sizing

["Grosso, Paul" <pgrosso@ptc.com>]

I have several questions about image sizing in DITA.  I
apologize in advance if we've already discussed these,
but I find it impossible to use the OASIS document archives
in any reasonable fashion.

Let me first point out that there are two areas involved 
when composing a document containing graphics (aka images):
(1) the "blank hole" on the page into which the image 
    will be placed.  This has been called the reproduction
    area (reproarea) by CALS.  This is what, in XSL FO,
    is specified by fo:external-graphic's height and width
    properties.
(2) the graphic image itself.  This is what, in XSL FO, 
    is specified by fo:external-graphic's content-height
    and content-width properties.

Regarding DITA's image element's height (and width) 
attributes, the DITA lang spec says:

  Indicates the maximum height (width) of an image.

It isn't clear to me whether this is really referring to
the reproarea dimensions or the graphic image dimensions.
At first glance, I'd assume these attributes are giving the 
actual desired image dimensions, but then why say "maximum ..."?

So just what--in terms of the two areas I describe above--are
the values of DITA's image element's height (and width) 
attributes specifying?

Also, the DITA lang spec says that the scale attribute (on 
the fig element) is "to allow authors to adjust font sizes 
on the content of the containing element, primarily for print 
accomodation [sic]. An image in these contexts is to be scaled 
only by its own direct scale property.  If not specifically 
scaled, such an image is unchanged by the scale property of 
its parent table or fig."

That seems to make it pretty clear that the scale property 
of the fig tag shouldn't affect the image.

Rather, it makes it sound like the image tag should have a 
scale property, but it doesn't.  Should it?

paul