--add-image and file paths with drive letter on Windows
When working on my eyed3 plugin I had to switch to a Windows machine for a bit and I noticed that the classic plugin will always split incoming arguments with a parameter value on a
However on Windows absolute paths usually include a drive letter plus the colon character thus causing for example
ImageArg to split the following path
['C', '\Users\Andre\Documents\picture.jpg', 'FRONT_COVER', 'Description']
ImageArg then assumes
C to be the path,
\Users\Andre\Documents\picture.jpg to be the type and thus fails.