code: public static void convert(InputStream srcStream, String formatName, OutputStream destStream) {
  		write(read(srcStream), formatName, getImageOutputStream(destStream));
  	}
docs: 图像类型转换：GIF=》JPG、GIF=》PNG、PNG=》JPG、PNG=》GIF(X)、BMP=》PNG<br>
  此方法并不关闭流
  
  @param srcStream 源图像流
  @param formatName 包含格式非正式名称的 String：如JPG、JPEG、GIF等
  @param destStream 目标图像输出流
  @since 3.0.9