CarrierWaveによって保存されたデータの中身。 - Qiita

[6] pry(main)> >> image_data = Attachment.find(7) image_data = Attachment.find(7) Attachment Load (0.5ms) SELECT `attachments`.* FROM `attachments` WHERE `attachments`.`id` = 7 LIMIT 1 => #<Attachment:0x00007f86e6d7b760 id: 7, knowledge_id: 17, sub_id: "1", name: "test.png", width_size: "1200", height_size: "799", file_type: "png", file_size: "72297", image: "test.png", thumb_image_url: "/uploads/