This has been sitting around my hard drive since it was first put together in 2013 to deal with a WooCommerce shop crushed with duplicat images. The import suite created duplicates for each combinatin of vairations that the products had, and each product had many variations (e.g. 5 colours, 6 sizes, 3 styles, giving 5x6x3=90 images, many of which were identical).
So test this thouroughly before using it. And have fun.
Installation to WordPress is through woo-import-image-fix-1.2.2.zip