ASP.NET

<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf89hAAAAB3RJTUUH2AQPB0tAAAAARnQU1" />

var part1 = 'iVBORw0KGgoAAAANSUhEUgAAABAAAAA';
var part2 = 'QCAYAAAAf89hAAAA';
var part3 = 'B3RJTUUH2AQPB0';
var part4 = 'tAAAAARnQU1';
// you can name these variables something different 
// and put them in different js-files making them more difficult to find.

<img src="" id="myImg"/>

// load the image like this
$(document).ready(function(){
  var base64src = 'data:image/png;base64,' + part1 + part2 + part3 +part4;
  $('#myImg').attr('src', base64src);
});

Dim currentRowIndex As Integer = Convert.ToInt32(e.Item.ItemIndex)
Session("Product") = DataList1.DataKeys(currentRowIndex)
ShoppingCart.Instance.AddItem(DataList1.DataKeys(currentRowIndex))

If currentRowIndex<0 Then
    'show an error message for negative values
ElseIf currentRowIndex>=DataList1.DataKeys.Count Then
    'show an error message that the index is to big
EndIf

If Not currentRowIndex > Integer.MinValue And currentRowIndex < Integer.MaxValue Then
    'Deal with the Error
Else    
    'now run the code

End If

if (!IsPostBack)
    {
        using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["PersonTest"].ConnectionString))
        {
            conn.Open();
            using (SqlCommand cmd = new SqlCommand("SELECT CityName , id FROM City", conn))
            {
                DataTable dt = new DataTable();
                SqlDataAdapter adpt = new SqlDataAdapter(cmd);
                adpt.Fill(dt);
                DropCity.DataTextField = "CityName";
                DropCity.DataValueField = "CityId";
                DropCity.DataBind();//You was missing this line.
            }
        } 
    }