I wrote a Python script to copy mp3 ID3 metadata with album art from all files in the source folder to the corresponding file in the destination folder. I have lots of old mp3 files which are of low bit rate and I have new files with higher bit rate. I like keeping offline copy of music file than streaming all the time. The newer files don't have metadata information. For the old files I had added them manually along with album art. It would be painstakingly time-consuming to manually add them again. The script is at GitHub mp3-copy-id3-metadata repository.