E puoi darci l'output sql per entrambe le tabelle?
In sql cambia id_product = 1 al tuo da product.
Migliore per ID prodotto.
select a.id_image, a.cover, b.id_image as id_image_shop, b.cover as cover_shop from ps_image a left join ps_image_shop b on (a.id_image = b.id_image) where a.id_product = 1;
Per esempio: