Using the Library: poi-src-2.5-final-20040302

reading a XLS-File containing Images is possible. The subsequent creation of a 
XLS is possible but the file is erroneous.

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;


public class ReadWriteWorkbook {
	public static void main(String[] args) throws IOException {
		String fp= File.separator;
		
		String file = "someFile.xls";
		
		POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream
(file));
		HSSFWorkbook wb = new HSSFWorkbook(fs);
		
		HSSFSheet sheet = wb.getSheetAt(0);
		HSSFRow row = sheet.getRow(0);
		
		if (row == null)
			row = sheet.createRow(0);
		HSSFCell cell = row.getCell((short) 0);
		if (cell == null)
			cell = row.createCell((short) 0);
		cell.setCellType(HSSFCell.CELL_TYPE_STRING);
		cell.setCellValue("a test");

		// Write the output to a file
		FileOutputStream fileOut = new FileOutputStream("workbook.xls");
		wb.write(fileOut);
		fileOut.close();

	}
}