Web Forms :: How To Display Image On Text Index Changed

Here the form code - 

<div class="textmid2">Adviser Photo :</div><div class="textright">Adviser Sign :</div></div>
<div class="Row"><div class="view_img1">
<asp:ImageMap ID="imgADphoto" runat="server" Width="140px" Height="150px">
</asp:ImageMap> </div>
<div class="view_sign1">
<asp:ImageMap ID="imgADsign" runat="server" Width="200px" Height="70px">
</asp:ImageMap> </div>
 
Code Behind for form code - 

//code behind//
protected void txtCID_OnTextChanged(object sender, EventArgs e) {
SqlConnection cnn = new SqlConnection();
cnn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
cnn.Open();

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