Then upload your PNG picture and change the file name to lock 1.png (note: the file names cannot be the same).
Delete the original lock.png file after uploading, and then what? Lock 1.png can be changed to lock.png.
After the modification is completed, close the compression software, search the Internet for an APK signature software and re-sign, OK!
The reason why I told you the method instead of giving you the file directly is to let you understand the principle.
Just do more.
The above is a personal answer, please don't take it amiss!