A few people have mentioned that Yoshi-P is shedding his own skin in that pic... I think he's coming out of the skin of the Wandering Minstrel, his own custom NPC that he used to give us our Goobbue horns. The goggles and red of the NPC's torso are very clearly visible there. Perhaps that has meaning as well, that he's shedding the Minstrel NPC for ARR, but I hope not. He was an interesting NPC and had great potential for direct director-player interaction via NPC for the future.

Maybe it's just a fun picture with no deeper meaning though.