In Asp.net (c#),i'm not able to catch exception(FileNotFoundException) properly... i don't know the reason..Actually File s not there..But catch statement fails to catch the exception.. here is the code..

try
{
System.Drawing.Image imgg1 = System.Drawing.Image.FromFile(Server.MapPath("").ToString() + "\\images\\img1.jpg");
 }
 catch (FileNotFoundException)
{
 Response.Write("<script>alert('Please Select and upload Student's Photo');</script>");
       }