Visual Studio .NET - How to display image in image box after selecting item in dropdown list in asp.net

In my asp.net project i had give one dropdownlist and two image controls. Am connected dropdownlist with database already two images are saved for every id. My work is after am selecting item in dropdownlist it will show already saved images in this two image controls how to give this pls help and thanks in advance. 

You can bind the images dynamically from Database

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

ddlSocialIcons.Items.Insert(0, new ListItem("Select Any Icon ", " "));

}

protected void ddlSocialIcons_SelectedIndexChanged(object sender, EventArgs e)

{

if (ddlSocialIcons.SelectedItem == null)

return;

switch (ddlSocialIcons.SelectedItem.Value.ToString())

{

case "1":

imgSocialIcon.ImageUrl = "~/SocialIcons/06-facebook-128.png";

break;

case "2":

imgSocialIcon.ImageUrl = "~/SocialIcons/03-twitter-128.png";

break;

case "3":

imgSocialIcon.ImageUrl = "~/SocialIcons/80-google-plus-128.png";

break;

case "4":

imgSocialIcon.ImageUrl = "~/SocialIcons/47-skype-128.png";

break;

default:

imgSocialIcon.ImageUrl = "~/SocialIcons/noimage.png";

break;

}

}

Design form ;

<form id="form1" runat="server">

<div>

<asp:DropDownList runat="server" ID="ddlSocialIcons" AutoPostBack="true" OnSelectedIndexChanged="ddlSocialIcons_SelectedIndexChanged">

<asp:ListItem Text="FaceBook" Value="1" />

<asp:ListItem Text="Twitter" Value="2" />

<asp:ListItem Text="Google+" Value="3" />

<asp:ListItem Text="Skype" Value="4" />

</asp:DropDownList>

</div>

<div style="width: 50%; height: 50%">

<asp:Image ID="imgSocialIcon" runat="server" />

</div>

</form>

thank u sir but am connect dropdownlist to sql database i dont know how to display images in imagebox already images are saved in database how to retrive after am select this dropdown selected item