PDF to pngs

image_uploader.rb

# encoding: utf-8

class ImageUploader < CarrierWave::Uploader::Base
  attr_reader :file

  include CarrierWave::RMagick
  include Magick


  storage :file

  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  version :profile do
    process :resize_to_fit => [200,300]
  end

  version :thumb do
    if :pdf?
      process :converting => :file
    end
    process :resize_to_fill => [400,500]
  end

  protected

  def pdf?(new_image)
    if current_path.include? 'pdf'
      puts "it is pdf"
      true
    else
      puts "it is not pdf"
      false
    end
  end

  def converting(new_image)
    puts "Im in converting"
    manipulate! do |image, index|
      
      puts "model id is#{model.id}"
      
      @page = Page.create
      image.write(Rails.root.join('public', store_dir, "p#{index}.png"))
      @page.image = Rails.root.join('public', store_dir, "p#{index}.png")
      @page.save
      image
    end
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:
  # version :thumb do
  #   process :scale => [50, 50]
  # end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  # def extension_white_list
  #   %w(jpg jpeg gif png)
  # end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end

end

Hmm check out my slight modifications to this, simplifies your code a little bit.
https://gist.github.com/2576703/ebf14152ad47a51ef535385cea2b573e8d0e2519

Oh I didn't know I could do that with manipulate. Thanks, changed it in my code works well.