Image position changes when IP address is typed in the address instead of hostname

Question

I have a web site in ASP.NET MVC 2. I deployed it in the server. But when I browse the site, the image position behaves differently with ip address and host name on the URL.

http://mysite/applicationsite

http://192.28.252.13/applicationsite

I couldn't figure out why its behaving differently. The image is more to the left when used ip address instead of hostname or vice versa.

EDIT: I have the following div in the master page.

<div id="header">
     <img id="imgLogo" alt="Logo" src="<%=Url.GetContentUrl("Logo")%>" />
</div>

It uses the stylesheet as:

#header {
    margin:0 auto;
    width:969px;
}

#imgLogo {
    height:112px;
    width:300px;
}