How to add a skin into a minecraft name?

I've been searching through the internet lately and found that some names have skins for cracked mine craft is there a way i can add a skin into a name

for example: when you login into cracked minecraft you put a name and sometimes that name has a skin that everyone can see

Guest

DeadMau5 does, it's a blue mouse with big ears, but that's all I can think of.

Jack