Thumbnails product doesn't want to remove

hello,
I’m with the last version of woocommerce.
and when I add into my page product description, pictures are automatically added to the thumbnails under the main image product.
but if I remove it from the product description page. the pictures stays in the thumbnails on the product page. and I didn’t find anywhere where I can remove and selected the pictures I want as thumbnails.

is it clear?…:s
Any idea?

regards,

http://wordpress.org/extend/plugins/woocommerce/