ImageMagick shouldn't consider pdf as images

Author: nebirhos

lib/formtastic/inputs/dragonfly_input.rb

@@ -66,11 +66,16 @@ def fragment_upload_html
  builder.hidden_field("retained_#{method}")
  end
 
+ def is_image?(file)
+ ![:pdf].include?(file.format) && file.image?
+ rescue
+ nil
+ end
+
  def fragment_preview_html
- image = object.send(method)
- if image.present?
- is_image = image.image? rescue false
- if is_image
+ file = object.send(method)
+ if file.present?
+ if is_image?(file)
  original_url = object.send(method).url
  preview_size = input_html_options[:preview_size] || [ 75, 75 ]
  preview_url = object.send(method).thumb("#{preview_size.first}x#{preview_size.last}#").url