I can't confirm the validity of these two pictures of AMD's (what's claimed to be) mainstream HD 7770.
This card is the first major upgrade to the HD 5770 in two years, since the HD 6770 was just a rebrand. It features the Cape Verde GPU, which replaces the Juniper GPU used in the HD 5770/HD 6770. The card looks somewhat different, with a large fan sitting on top of the GPU, blowing directly onto it and the card's length is the same as the HD 5770, at around 8.25 inches.