file upload

protected void btnsave_Click(object sender, EventArgs e)
    {

        if (FileUpload1.HasFile == false)
        {

            lblpicname.Text = "Please select a file";
        }
        else
        {
        FileUpload1.SaveAs(Server.MapPath("~") + "//profiles//" + FileUpload1.FileName);
        lblpicname.Text = FileUpload1.FileName;
        if (FileUpload1.HasFile)
        {
            string extension = System.IO.Path.GetExtension(FileUpload1.FileName);

            if (extension == ".jpg" || extension == ".jpeg" || extension == ".png" || extension == ".JPG" || extension == ".JPEG" || extension == ".PNG" || extension == ".BMP")
            {


                FileUpload1.SaveAs(Server.MapPath("~") + "//profiles//" + FileUpload1.FileName);
                lblpicname.Text = FileUpload1.FileName;
                update();
                show();

            }
            else
            {


                ScriptManager.RegisterStartupScript(this, this.GetType(), "alertmessage", "javascript:alert('Only .jpg,jpeg,png,bmp File allowed')", true);

            }
        }
            

        }

        
        
    }