Two Tone Sigs?

[zLeedlez]

Its really annoying me now, I can see some sigs have two tones for the forum background in them.
Like this but you can only see it on the bigger images (Focus on the right)

 

if ur using google chrome then it's cuz of their color correction

 

its on your end

Gyazo - 42768477a4f0942c4ab75ddb4a168323.png