Added reprocess! method. The rake task will actually reprocess the da…

…ta it has now instead of ignoring it.

lib/paperclip/attachment.rb

@@ -153,6 +153,22 @@ def self.interpolations
       }
     end
 
+    # This method really shouldn't be called that often. It's expected use is in the
+    # paperclip:refresh rake task and that's it. It will regenerate all thumbnails
+    # forcefully, by reobtaining the original file and going through the post-process
+    # again.
+    def reprocess!
+      new_original = Tempfile.new("paperclip-reprocess")
+      old_original = to_file(:original)
+      new_original.write( old_original.read )
+      new_original.rewind
+
+      @queued_for_write = { :original => new_original }
+      post_process
+
+      old_original.close if old_original.respond_to?(:close)
+    end
+
     private
 
     def valid_assignment? file #:nodoc:

tasks/paperclip_tasks.rake

@@ -25,7 +25,7 @@ namespace :paperclip do
     instances.each do |instance|
       names.each do |name|
         result = if instance.send("#{ name }?")
-          instance.send(name).send("post_process")
+          instance.send(name).reprocess!
           instance.send(name).save
         else
           true