Creating minimal previews

[Sven Axelsson]

I create preview images for the music published on my website.
Some of the pieces are made up of a \book containing up to
10 \score parts. In this case the preview image the preview
image is made up of the first system of all 10 parts. Now, I
would rather have a preview consisting only of the first system 
of the first score. I figure I can do this by creating a
temporary .ly file where I extract the stuff I need using a
Python script or such. But maybe there is a better way?

Perhaps this would be useful for others as well, so it could
be added to Lilypond (as a sponsored feature) by adding a
--minimal-preview flag to the program?

-- 
Sven Axelsson