I too can't see how this cover can be seen as in any way related to disability. Perhaps Sondra can explain clearly how she reads the image in this way?I always took it to be a shop mannikin figure of Nic showing his hidden material. and the dog does look to be burying rather than unearthing , but where is the disability aspect?
I personally don't like the cover because it is a rather feeble idea, a bit like those joke birthday cards which are funny for about 2 seconds and reading it is a corpse is a bit unsettling. On an album which is going to be around for ever something a bit more interesting would be in better keeping.
However it is a GREAT album and after a week or two most people would become oblivious to the cover art. Don't let it put you off!