端末で実行します
rake -T paperclip
このように見ることができます
...
rake paperclip:clean # Cleans out invalid attachments.
rake paperclip:refresh # Refreshes both metadata and thumbnails.
rake paperclip:refresh:metadata # Regenerates content_type/size metadata for a given CLASS (and optional ATTACHMENT).
rake paperclip:refresh:missing_styles # Regenerates missing thumbnail styles for all classes using Paperclip.
rake paperclip:refresh:thumbnails # Regenerates thumbnails for a given CLASS (and optional ATTACHMENT and STYLES splitted by comma).
...
サムネイルを更新するには、これを試してください
rake paperclip:refresh:thumbnails class= Xyz # xyz replace with your class name
除去用
rake paperclip:clean # Cleans out invalid attachments.