diff --git a/config/initializers/paperclip.rb b/config/initializers/paperclip.rb
index 868ff2c55..7ac23bbe9 100644
--- a/config/initializers/paperclip.rb
+++ b/config/initializers/paperclip.rb
@@ -80,7 +80,7 @@ Paperclip::Attachment.class_eval do
   end
 
   def previewable_image?
-    content_type == %r{^image/#{Regexp.union(Constants::WHITELISTED_IMAGE_TYPES)}}
+    content_type =~ %r{^image/#{Regexp.union(Constants::WHITELISTED_IMAGE_TYPES)}}
   end
 end
 
diff --git a/lib/paperclip/image_quality_calculate.rb b/lib/paperclip/image_quality_calculate.rb
index 8927e5391..7a3f185ac 100644
--- a/lib/paperclip/image_quality_calculate.rb
+++ b/lib/paperclip/image_quality_calculate.rb
@@ -12,8 +12,22 @@ module Paperclip
         @attachment.instance.file_image_quality = quality.to_i
         # Asset will be save after all processors finished
       end
-      # We need again open file after read quality
-      File.new(File.expand_path(@file.path))
+
+      # We have to create a new temp file otherwise the postprocessing logic will
+      # delete the original file, leaving no files to postprocess for styles
+      current_format = File.extname(attachment.instance.file_file_name)
+      basename = File.basename(@file.path, current_format)
+      tempfile = Tempfile.new([basename, current_format].compact.join('.'))
+
+      begin
+        tempfile.write(File.read(@file.path))
+        tempfile.flush
+        tempfile
+      rescue StandardError => e
+        tempfile.close
+        tempfile.unlink
+        raise Paperclip::Error, "There was an error writing to tempfile - #{e}"
+      end
     rescue StandardError => e
       raise Paperclip::Error, "There was an error processing the image - #{e}"
     end