If inside ImageUrl

I need to display the image link using an If, the false part of the if works, but the true doesn't, which is a variable. If i do a response.write in the variable imageFileLink it shows the link, but when I load the page with the variable in the if, it doesn't...

Thanks

<asp:Image ID="Image1" runat="server" ImageUrl='<%# If (Eval("recImage") is DBNull.Value, String.Format("{0}", imageFileLink), String.Format("data:image/jpg;base64,{0}", Encoding.UTF8.GetString(Eval("recImage"))))%>' />