All you have to do is edit the LockBackground.html file.
iFile 打开blink 主题包
点击lockbackground.html 使用 text viewer 打开
然后点击左上角的 edit 修改
background:url('/private/var/mobile/Library/SpringBoard/LockBackground.jpg');
去
The new line will look like this: background:url('/private/var/mobile/Library/SpringBoard/LockBackgroundThumbnail.jpg');