I am making use of some of the hooks like mcc_term_copied and mcc_copy_post_meta to copy over meta data including images for posts and terms. This works well, thanks for adding these hooks. When copying these files over I check whether they do already exist. However, because the meta is copied before attachments are copied, the attachments are copied twice. Would it be possible to check whether the attachment already exist when copying them over? Maybe making use of the slug to check whether attachments exist? I think the method where to check is Multisite_Content_Copier_Post_Type_Copier::copy_attachment_element().