@{
var imagePath="";
if( Request["Choice"] != null)
   {imagePath="images/" + Request["Choice"];}
}
<!DOCTYPE html>
<html>
<body>
<h1>Display Images</h1>
<form method="post" action="">
I want to see:
<select name="Choice">
   <option value="Pic1.jpg">Photo 1</option>
   <option value="Pic2.jpg">Photo 2</option>
   <option value="Pic3.jpg">Photo 3</option>
</select>
<input type="submit" value="Submit">
@if(imagePath != "")
{
<p>
<img src="@imagePath" alt="Sample">
</p>
}
 
</form>
</body>
</html>