Just to note some of the history on this.  When a very sensible 
(*cough cough*) TEI Bug report was submitted in 2009-06 asking 
for <graphic> to have <desc>, two of the comments from 2009-12-11 
(one by Gaby and the other by myself) suggested at the time that 
one of the reasons that <graphic> should have <desc> or 
model.glossLike was for categorization of the images pointed at, 
e.g. hi-res, low-res, etc.  Moreover, it was suggested at the 
time that it get att.typed as well.

One of the reasons given was that there was plenty of instances 
where one had <graphic> available but not <figure>.  In any case 
whenever you have a <graphic> if you are producing html:img with 
it, you should be producing an html:img/@alt attribute with alt 
text in it. In those cases, such as inside facsimile, you now 
have <desc> (and <gloss>?) as child to provide this.

I'm still of the opinion, as in the comment from 2009-12-11, that 
graphic should have a @type attribute to enable classification of 
what 'type' of graphic it is.  (Note: this is a separate 
classification from its @mimeType)


Dr James Cummings, Research Technologies Service
OUCS, University of Oxford