I'm looking for a Windows tool which adds cover art to MP3 files, preserving existing ID3 tags, so I can use it in scripts, like
"tool.exe folder.jpg title.mp3"
I don't care if it's a console application or not, it should just accept command line parameters (with no output).
I found a tool doing exactly such thing called "MetaMP3 v0.92 beta 5" (about four years old) but the tool isn't unicode and messing up ID3tags with international characters.
The next best - and only - thing is probably eyeD3, but I can't figure out how to get this Python source compiled.
My extensive Internet search also brought up "Tag", which is pretty cool to extract Id3v2 info, but it can't write id3v2.
"tool.exe folder.jpg title.mp3"
I don't care if it's a console application or not, it should just accept command line parameters (with no output).
I found a tool doing exactly such thing called "MetaMP3 v0.92 beta 5" (about four years old) but the tool isn't unicode and messing up ID3tags with international characters.

The next best - and only - thing is probably eyeD3, but I can't figure out how to get this Python source compiled.

My extensive Internet search also brought up "Tag", which is pretty cool to extract Id3v2 info, but it can't write id3v2.













Could've saved me some work. 
In hindsight, I really should have mentioned that method but it wasn't a commandline method as per your original request.