We've just copied and pasted this off Twitpic.
Someone on the Popjustice forum says that this sleeve artwork is a bit low budget but that can hardly be the case when you think about it. First of all they had to get all the girls together at the same time to take the photo — no mean feat when you have five individual style queens on your hands!! — then there was the expensive image manipulation afterwards in which a highly skilled team of graphic designers Photoshopped the picture in order to bring to life the artwork's highly-stylised vision — that it should look as if the girls actually had their photographs taken separately.
Quite the achievement!
It is a bit like the Hurts sleeve.
You might think, 'this is two separate photos clearly chucked together, you can tell from the way the shadows fall on their faces', but actually Theo and Adam were photographed together, with the extra light source added at the time at vast addition expense. (Probably.)
In summary: pop is not shoddy, it is all on purpose.