C# is case sensitive language...so both eval and Eval is different...and the method for binding is Eval not eval..so you can try like this
<%# ((string)Eval("fld_status") == "0") ? "~/images/arrow_yes.png" : ((string)Eval("fld_status") == "1") ? "~/images/edit_msg.png" : "~/images/arrow_down.png" %>