diff --git a/app/models/attachment.rb b/app/models/attachment.rb
index fd4931eaf..ac9561c26 100644
--- a/app/models/attachment.rb
+++ b/app/models/attachment.rb
@@ -216,7 +216,7 @@ class Attachment < ActiveRecord::Base
         size = Setting.thumbnails_size.to_i
       end
       size = 100 unless size > 0
-      target = File.join(self.class.thumbnails_storage_path, "#{digest}_#{filesize}_#{size}.thumb")
+      target = thumbnail_path(size)
 
       begin
         Redmine::Thumbnail.generate(self.diskfile, target, size)
@@ -463,6 +463,14 @@ class Attachment < ActiveRecord::Base
     if disk_filename.present? && File.exist?(diskfile)
       File.delete(diskfile)
     end
+    Dir[thumbnail_path("*")].each do |thumb|
+      File.delete(thumb)
+    end
+  end
+
+  def thumbnail_path(size)
+    File.join(self.class.thumbnails_storage_path,
+              "#{digest}_#{filesize}_#{size}.thumb")
   end
 
   def sanitize_filename(value)
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 15936c39e..c9e94b31c 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -457,6 +457,21 @@ class AttachmentTest < ActiveSupport::TestCase
       assert_equal a_thumb, b_thumb
     end
 
+    def test_destroy_should_destroy_thumbnails
+      a = Attachment.create!(
+        :container => Issue.find(1),
+        :file => uploaded_test_file("2010/11/101123161450_testfile_1.png", "image/png"),
+        :author => User.find(1)
+      )
+      diskfile  = a.diskfile
+      thumbnail = a.thumbnail
+      assert File.exist?(diskfile)
+      assert File.exist?(thumbnail)
+      assert a.destroy
+      refute File.exist?(diskfile)
+      refute File.exist?(thumbnail)
+    end
+
     def test_thumbnail_should_return_nil_if_generation_fails
       Redmine::Thumbnail.expects(:generate).raises(SystemCallError, 'Something went wrong')
       set_fixtures_attachments_directory