sorting

Hi i have a problem in the usage of the grid for teh images. When i load the images(present in the theme folder) and click on column header(the column contains the data+ image) am getting the column sorted based on image. Can i have the columns sorted based on the data?am getting the images + data as follows--

if("xls".equalsIgnoreCase(extnTYP)){
            //								gridDataArr.append("\"" + "XLS"+"<img src='../theme/xlsheet.JPG'></img>" + "\",");
            //						
            //				
            //					}else if("ppt".equalsIgnoreCase(extnTYP)){
            //								gridDataArr.append("\"" + "PPT"+"<img src='../theme/powerppt.JPG'></img>" + "\",");
            //						
            //					}else if("doc".equalsIgnoreCase(extnTYP)||"rtf".equalsIgnoreCase(extnTYP)){
            //								gridDataArr.append("\"" +"DOC"+ "<img src='../theme/worddoc.JPG'></img>" + "\",");
            //						
            //					}else if("pdf".equalsIgnoreCase(extnTYP)){
            //								gridDataArr.append("\"" + "PDF")+ "<img src='../theme/pdfimage.JPG'></img>" + "\",");
            //					
            //					}