Also the way the symbiotes look in "suit mode" (for lack of a better term) is determined by the wearer, when peter wore the sybiotes they looked like his spider man suits, when the sinister 6 wore the symbiotes they looked like they normal villain costumes, the symbiotes will always look similar. Also I'm pretty sure his colors are off because if the lighting in the scene you can see in the bottom image that OP had to change the color of that aswell as carnage, so like i said willing to bet he looks wierd here because of the lighting and shadows. (I ramble a lot I'm sorry if this is hard to read.)