"I went to the store to get my photos developed but they had already closed."
"I went to the shop to develop my photos but it had already closed."
"I went to get my photos developed but the shop had already closed."
"developed" - to develop 「現像する」
"already" 「すでに」
"store" と "shop" どちら使っても大丈夫で、"camera store" や "camera shop" も使えます。
一つ目の文 "...but they had already closed." の "they" はお店の店員さんがお店を閉店した事を表し、二つ目の文の "it" はお店がもう閉店した事を表します。
"photos" の代わりに "film" 「カメラフィルム」も使えます。"I went to the store to get my film developed..."
I went to the shop to develop my photos, but it was already closed.I went to the shop to develop my photos, but it was already closed.
I went to the shop to develop my photos, but it was already closed.
I went to get my photos developed, but the store had already shut.
「写真を現像するために店に行ったが、既に閉店していた」という内容を伝えるには、「develop my photos(写真を現像する)」と、「already closed(すでに閉まっていた)」という表現がカギになります。
「写真を現像する」は英語では **develop photos** または **get photos developed** と言います。"develop" はもともと「現像する」という意味の動詞です。