How to send background image on div in ASP .NET?

<pre lang="text">
<img src="cid:image1" />
<div style="background-image:url(cid:image2)">
<p>This is Text!</p>
</div>
</pre>

Email Code.

string image1Path= HttpContext.Current.Server.MapPath(@"~/Images/image1.png");
string image2Path= HttpContext.Current.Server.MapPath(@"~/Images/image2.png");

 LinkedResource lnk1= new LinkedResource(image1Path);
 LinkedResource lnk2= new LinkedResource(image2Path);

 lnk1.ContentId = "image1";
 lnk2.ContentId = "image2";

AlternateView av1 = AlternateView.CreateAlternateViewFromString("" + htmlTemplate, null, MediaTypeNames.Text.Html);
      

av1.LinkedResources.Add(image1);
av1.LinkedResources.Add(image2);
       
message.AlternateViews.Add(av1);