where can i edit the masthead image size

Hi,

I’m using vantage and edit it first in my localhost, i upload a header logo and the original size is 1080px by 227px. i already change the padding to zero so that the white spaces will not show, i am confuse because i can’t see the location of the image size in the style.css to edit it butwhen i’m inspecting it using chrome inspect element i saw this

<img src=”https://localhost/hospital/wp-content/uploads/logo2.png&#8221; width=”1010″ height=”212″ alt=”Hospital Management Asia 2014 Logo”>.

thanks in advance