That pic is GREAT! Who wants to bet that the decepticon symbol was originaly a paint splatter?
as far as i can tell, it looks like megatron is carrying out his first evil act, brutally murdering someone - his autobot boss? because he's sick of taking orders? - and their internal fluids are splattering on him. a bunch of other people see what he's done, and decide to rebel with him, and take the splatter of the blood of their oppressor as being a sign of all that the movement signifies.. taking your destiny into your own hands instead of dedicating your life to serving others.. what it means to be a decepticon
but then, thats just a guess.