When a local cover image is uploaded, the image ("full" and thumbnail) and the connection to the biblio record are stored in the "cover_images" table: https://schema.koha-community.org/23_11/tables/cover_images.html Some information is also stored in the "uploaded_files" table: https://schema.koha-community.org/23_11/tables/uploaded_files.html Would it not make sense to connect these to, so cover_images contained a reference to the relevant entry in uploaded_files? That way we could also make a connection from biblionumber to any existing files in "tmp_path" directories.