OOP cover- a Dementor?

[btk6y]

No: HPFGUIDX 54031

Interestingly, my first look at the OOP cover had me think of the 
Dementors.  I just always have the image of Harry in Lupins 
classroom in PoA:

"..the lamps around the classroom flickered and went out.."

What if a whole horde of Dementors just walked in and the candles 
are about to go out?  This would also explain the look of 
determination on Harry's face as he is about to conjure up the 
mother of all Patronus charms.  I was also considering, could the 
setting of the picture be Azkaban?  The doors are not likely to be 
going into prisoner rooms since Sirius stated that there were bars 
on the cell doors (he was so thin as a dog he slipped through the 
bars, etc).  But it could be someplace in Azkaban... if not, I vote 
for the room with special powers since JKR obviously thinks it is a 
cool place and Harry will need all the help he can get if a horde of 
dementors walks into the room to take over Hogwarts.  

Incidently, I don't know how useful it is to analyze Harry's 
expression to death... considering the gigantic smile he has on his 
face in the GoF cover- if we were to extrapolate from that 
expression to the book plot we would have been way off.  

Bobby