Paperclip vs CarrierWave

carrierwave.rb

class ImageQuestion < TextQuestion
  store :data, accessors: [:image]
  mount_uploader :image, ImageUploader

  validates :image, download: true, processing: true
end

class ImageUploader < CarrierWave::Uploader::Base
  include CarrierWave::MiniMagick

  resize_to_limit nil, 800

  version :resized do
    resize_to_limit nil, 250
  end
end

paperclip.rb

require "active_support/core_ext/numeric/bytes"
require "active_support/inflector/transliterate"
require "uri"

class ImageQuestion < TextQuestion
  store :data,
    accessors [:image_file_name, :image_content_type,
               :image_file_size, :image_updated_at, :image_size]

  has_attached_file :image, styles: {resized: "x250>"},
    whiny: false

  validates_attachment :image,
    presence: {if: -> { [image_url, image_file].all?(&:blank?) }},
    content_type: {content_type: ["image/jpeg", "image/gif", "image/png"], allow_blank: true},
    size: {in: 0..1.megabyte}
  validate :validate_image_url

  attr_reader :image_url
  def image_url=(url)
    begin
      @image_url = url
      self.image = URI.parse(url)
    rescue
      self.image = nil
    end if url.present?
  end

  attr_reader :image_file
  def image_file=(file)
    begin
      @image_file = file
      self.image = SanitizedFile.new(file)
    rescue
      self.image = nil
    end if file.present?
  end

  private

  def validate_image_url
    if image_url.present? and image.blank?
      errors.add(:image_url, :invalid)
    end
  end

  class SanitizedFile < SimpleDelegator
    include ActiveSupport::Inflector

    # Because Paperclip chooses the adapter for uploaded files
    # by looking at the class name
    def self.name
      "UploadedFile"
    end

    def original_filename
      transliterate(__getobj__.original_filename)
    end
  end
end