Image not dispaly in MAC Excel

Question

Hi, to  one and all,please help me i am generating excel report using below code
StringBuilder sb = new StringBuilder();
            sb.Append("<table border='1' width='100%'>");
            sb.Append("<tr><td style='height:60px'><img src='" + ConfigurationManager.AppSettings["ExcelReportsImage"] + "Images\\cl-report-logo.gif'></td></tr>");
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// getting data from dataset and append using string builder.
-----
sb.Append("</table>");
            System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
            oStringWriter.Write(sb.ToString());
            System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
            Repeater rt = new Repeater();
            rt.RenderControl(oHtmlTextWriter);
            Response.Write(oStringWriter.ToString());
            Response.End();

this code is working in windows butin mac system excel is genated with data fine but the image is not displayed it getting below error msg is attached here.

i am given virtuval path in ConfigurationManager.AppSettings["ExcelReportsImage"] . plese help me. thi s the only problem in mac system ms office excel report.