There is a repro of that cel, the question 
remains whether the one you're interested in is 
the real deal.  I've seen it in someone's gallery 
and a somewhat different one (with respect to the 
hand-drawn parts) on ebay last February.  I 
cannot tell the difference between the picture 
you posted and the one on ebay. Although it's 
really hard to tell (because it comes from a 
strongly backlit sequence in OVA 5), I've 
convinced myself that both cels are repros (which 
isn't to say that I really know).  The ebay cel 
is missing a purple-colored area (colored in 
green in the picture below) that is present in 
the one in the gallery (and that I think I see in 
the video).  Perhaps someone with a DVD or LD 
copy can confirm that.  A more detailed scan of 
the full cel would be useful, since some of the 
highlights in Belldandy's hair (that have been 
cut off in the photo you have but are in the 
other two cels) look unlike the video to me.