Workbook workbook = new Workbook("C:/test2.xlsx");
Picture picture = workbook.getWorksheets().get(0).getPictures().get(0);
ImageOrPrintOptions options = new ImageOrPrintOptions();
options.setSaveFormat(SaveFormat.SVG);
picture.toImage("pic.svg", options);
pic.svg is blank in browser, and svg use embbeded image by data:image/bmp;base64, but bmp is opaque.