Model
has_attached_file :foto
validates_attachment_content_type :foto, content_type: /\Aimage\/.*\z/
Error in log
Command :: file -b --mime "C:/Users/conta/AppData/Local/Temp/66c9eed121277d8be2df09ce25c4687a20171106-5872-1j1pihz.jpg"
[paperclip] Content Type Spoof: Filename foto.jpg (image/jpeg from Headers, ["image/jpeg"] from Extension),content type discovered from file command: . See documentation to allow this combination.