diff --git a/.gitignore b/.gitignore
index d4484ab46..54e603b88 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,4 @@ test/dummy/public/uploads/*
 .DS_Store
 Gemfile.lock
 dragonfly.log
+public/
diff --git a/lib/ckeditor/backend/shrine.rb b/lib/ckeditor/backend/shrine.rb
index 532186e72..b991cecd2 100644
--- a/lib/ckeditor/backend/shrine.rb
+++ b/lib/ckeditor/backend/shrine.rb
@@ -9,11 +9,11 @@ def self.included(base)
 
       module InstanceMethods
         def data=(value)
-          self.attachment_data = value
+          self.attachment = value
         end
 
         def url
-          attachment.url
+          attachment&.url
         end
 
         def data_file_name
diff --git a/lib/generators/ckeditor/install_generator.rb b/lib/generators/ckeditor/install_generator.rb
index 80b1ab403..e56ac9e22 100644
--- a/lib/generators/ckeditor/install_generator.rb
+++ b/lib/generators/ckeditor/install_generator.rb
@@ -51,15 +51,15 @@ def create_models
 
       def create_uploaders
         if backend_carrierwave?
-          template "#{uploaders_dir}/uploaders/ckeditor_attachment_file_uploader.rb",
+          template "#{uploaders_dir}/ckeditor_attachment_file_uploader.rb",
                    File.join('app/uploaders', 'ckeditor_attachment_file_uploader.rb')
 
-          template "#{uploaders_dir}/uploaders/ckeditor_picture_uploader.rb",
+          template "#{uploaders_dir}/ckeditor_picture_uploader.rb",
                    File.join('app/uploaders', 'ckeditor_picture_uploader.rb')
         end
 
         if backend_shrine?
-          template "base/shrine/attachment_uploader.rb",
+          template "#{uploaders_dir}/ckeditor_attachment_uploader.rb",
                    File.join('app/uploaders', 'ckeditor_attachment_uploader.rb')
         end
       end
@@ -94,7 +94,7 @@ def generator_dir
       end
 
       def uploaders_dir
-        @uploaders_dir ||= 'base/carrierwave'
+        @uploaders_dir ||= "base/#{backend}/uploaders"
       end
 
       def orm
diff --git a/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/asset.rb b/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/asset.rb
index 37dd78041..ded33403d 100644
--- a/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/asset.rb
+++ b/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/asset.rb
@@ -5,4 +5,6 @@ class Ckeditor::Asset < ActiveRecord::Base
   include Ckeditor::Backend::Shrine
 
   include CkeditorAttachmentUploader::Attachment(:attachment)
+
+  validates :attachment_data, presence: true
 end
diff --git a/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/picture.rb b/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/picture.rb
index e71046ddc..6920853df 100644
--- a/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/picture.rb
+++ b/lib/generators/ckeditor/templates/active_record/shrine/ckeditor/picture.rb
@@ -2,10 +2,10 @@
 
 class Ckeditor::Picture < Ckeditor::Asset
   def url_content
-    attachment.url
+    attachment&.url
   end
 
   def url_thumb
-    attachment.url
+    attachment&.url
   end
 end
diff --git a/lib/generators/ckeditor/templates/base/shrine/attachment_uploader.rb b/lib/generators/ckeditor/templates/base/shrine/attachment_uploader.rb
deleted file mode 100644
index 0a36f5e2b..000000000
--- a/lib/generators/ckeditor/templates/base/shrine/attachment_uploader.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-class CkeditorAttachmentUploader < Shrine
-  # plugins and uploading logic
-end
diff --git a/lib/generators/ckeditor/templates/base/shrine/uploaders/ckeditor_attachment_uploader.rb b/lib/generators/ckeditor/templates/base/shrine/uploaders/ckeditor_attachment_uploader.rb
new file mode 100644
index 000000000..30d7921f2
--- /dev/null
+++ b/lib/generators/ckeditor/templates/base/shrine/uploaders/ckeditor_attachment_uploader.rb
@@ -0,0 +1,8 @@
+class CkeditorAttachmentUploader < Shrine
+  plugin :validation_helpers
+
+  Attacher.validate do
+    validate_max_size 5*1024*1024 # file size must not be greater than 5 MB
+    validate_min_size 1024        # file size must not be less than 1 KB
+  end
+end
diff --git a/test/controllers/attachment_files_controller_test.rb b/test/controllers/attachment_files_controller_test.rb
index d6a879fce..8f86878bb 100644
--- a/test/controllers/attachment_files_controller_test.rb
+++ b/test/controllers/attachment_files_controller_test.rb
@@ -6,7 +6,8 @@ class AttachmentFilesControllerTest < ActionController::TestCase
   tests Ckeditor::AttachmentFilesController
 
   def setup
-    @attachment = fixture_file_upload('files/rails.tar.gz', 'application/x-gzip')
+    @attachment = Rack::Test::UploadedFile.new('test/dummy/test/fixtures/files/rails.tar.gz', 'application/x-gzip')
+
     @routes = Ckeditor::Engine.routes
   end
 
diff --git a/test/controllers/pictures_controller_test.rb b/test/controllers/pictures_controller_test.rb
index 35685dad8..011fbc843 100644
--- a/test/controllers/pictures_controller_test.rb
+++ b/test/controllers/pictures_controller_test.rb
@@ -6,7 +6,7 @@ class PicturesControllerTest < ActionController::TestCase
   tests Ckeditor::PicturesController
 
   def setup
-    @image = fixture_file_upload('files/rails.png', 'image/png')
+    @image = Rack::Test::UploadedFile.new('test/dummy/test/fixtures/files/rails.png', 'image/png')
     @routes = Ckeditor::Engine.routes
   end
 
diff --git a/test/models/picture_test.rb b/test/models/picture_test.rb
index 57809b91e..4de3b3390 100644
--- a/test/models/picture_test.rb
+++ b/test/models/picture_test.rb
@@ -10,7 +10,8 @@ def teardown
   test 'Set file content_type and size' do
     @picture = create_picture
 
-    assert_equal 'rails.png', @picture.data_file_name unless CKEDITOR_BACKEND == :shrine
+    assert_equal 'rails.png', @picture.data_file_name
+
     case CKEDITOR_BACKEND
     when :dragonfly
       assert @picture.url_thumb.include?('thumb_rails')
@@ -18,7 +19,6 @@ def teardown
       assert @picture.url_thumb =~ /\/representations\/.*\/rails.png/
     when :shrine
       assert @picture.url_thumb =~ /\S{32}\.png/
-      assert @picture.data_file_name =~ /image_processing(\d{8})-(\d{5})-(\S{,7})\.png/
     else
       assert @picture.url_thumb.include?('thumb_rails.png')
     end
diff --git a/test/support/helpers.rb b/test/support/helpers.rb
index 7971d6a3a..61431a25a 100644
--- a/test/support/helpers.rb
+++ b/test/support/helpers.rb
@@ -7,7 +7,7 @@ class ActiveSupport::TestCase
   include ActionDispatch::TestProcess
 
   def new_attachment(data = nil)
-    data ||= fixture_file_upload('files/rails.tar.gz', 'application/x-gzip')
+    data ||= Rack::Test::UploadedFile.new('test/dummy/test/fixtures/files/rails.tar.gz', 'application/x-gzip')
 
     Ckeditor.attachment_file_model.new(data: data)
   end
@@ -19,7 +19,7 @@ def create_attachment(data = nil)
   end
 
   def new_picture(data = nil)
-    data ||= fixture_file_upload('files/rails.png', 'image/png')
+    data ||= Rack::Test::UploadedFile.new('test/dummy/test/fixtures/files/rails.png', 'image/png')
 
     Ckeditor.picture_model.new(data: data)
   end