Hey James. Maybe 'generateRandomImages.php' might be helpful?
$ php path/to/mediawiki/tests/phpunit/includes/api/generateRandomImages.php
A little more information here:
https://www.mediawiki.org/wiki/Extension:UploadWizard#Testing
And I mean a little. :( Hope that helps.
Yours,
Chris Koerner
clkoerner.com