/** 保存方法 */
 public void saveBitmap() {
  Log.e(TAG, "保存图片");
  File f = new File("/sdcard/namecard/", picName);
  if (f.exists()) {
   f.delete();
  }
  try {
   FileOutputStream out = new FileOutputStream(f);
   bm.compress(Bitmap.CompressFormat.PNG, 90, out);
   out.flush();
   out.close();
   Log.i(TAG, "已经保存");
  } catch (FileNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

}

在这里还需要两个权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>