Custom VIP icon ServiceNow

Create an image in image module
get the name of the image (Example: VIP.gif)
Go to Caller Field->Configure styles->style->

background-image: url('VIP.png');
background-repeat: no-repeat;
background-position: center center;
padding-right: 30px;

Go to Client Scripts-> Highlight VIP Caller->change the URL to updated one

before :

callerLabel.setStyle({backgroundImage: "url('images/icons/vip.gif')", backgroundRepeat: "no-repeat", backgroundPosition: bgPosition, paddingLeft: '30px' });
callerField.setStyle({color: "red"});


after:

callerLabel.setStyle({backgroundImage: "url('VIP.png')", backgroundRepeat: "no-repeat", backgroundPosition: bgPosition, paddingLeft: '30px' });
callerField.setStyle({color: "red"});