I used the below code to export content and image to excel, the data is rendering in excel but not an image(excel is not rendering base64 image). Any ideas to export image as well with this implementation ?

Code:
StringWriter tw = new StringWriter();
HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
var result = (DataTable) TempData["Report"];         
DataGrid dgGrid = new DataGrid();
dgGrid.DataSource = result;
dgGrid.DataBind();
Image img = new Image();
img.ImageUrl = "data:image/png;base64,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...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";
dgGrid.RenderControl(hw);
img.RenderControl(hw);
string filename = DateTime.Now.ToShortDateString() + "_Report.xls";
Response.Clear();
Response.ContentType = "application/vnd.ms-excel";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + filename + "");
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Write(tw.ToString());
Response.End();