Pitch Premium – Sprites

Hi,

I’ve been messing with Pitch for a bit now and just recently bought the premium version. However, I’m finding it real difficult to change the colour of the Feature icon background.
When I analyze the element I get this:

#site-features .feature .icon {
background: url('images/sprites.png') no-repeat -31px -49px;
}

But there is no such png file in my web directory.

It calls something from a certain css sheet that I cannot find either:

/* =Sprite Map Replacement
-------------------------------------------------------------- */
#slider .indicators .indicator .pointer {
	background: url('images/sprites.png') no-repeat 0 -16px;
}
#site-features .feature .icon {
	background: url('images/sprites.png') no-repeat -31px -49px;
}

I already edited the sprites-1-3-7.png file to the colour I need but it isn’t showing on the page.
All I want to do is change the colour… can someone help me please?