diff --git a/.rubocop.yml b/.rubocop.yml
index b94e63629..af6fc7333 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -5,7 +5,7 @@ AllCops:
     - "vendor/**/*"
     - "db/schema.rb"
   UseCache: false
-  TargetRubyVersion: 2.5
+  TargetRubyVersion: 2.6
 
 ##################### Style ####################################
 
diff --git a/app/controllers/assets_controller.rb b/app/controllers/assets_controller.rb
index 00c5e918a..60caa59a6 100644
--- a/app/controllers/assets_controller.rb
+++ b/app/controllers/assets_controller.rb
@@ -63,7 +63,7 @@ class AssetsController < ApplicationController
   def file_preview
     response_json = {
       'id' => @asset.id,
-      'type' => (@asset.is_image? ? 'image' : 'file'),
+      'type' => (@asset.image? ? 'image' : 'file'),
 
       'filename' => truncate(escape_input(@asset.file_file_name),
                              length: Constants::FILENAME_TRUNCATION_LENGTH),
@@ -78,7 +78,7 @@ class AssetsController < ApplicationController
                  can_manage_repository_rows?(@repository.team)
                end
 
-    if @asset.is_image?
+    if @asset.image?
       if ['image/jpeg', 'image/pjpeg'].include? @asset.file.content_type
         response_json['quality'] = @asset.file_image_quality || 90
       end
@@ -322,7 +322,7 @@ class AssetsController < ApplicationController
 
   def asset_data_type(asset)
     return 'wopi' if wopi_file?(asset)
-    return 'image' if asset.is_image?
+    return 'image' if asset.image?
 
     'file'
   end
diff --git a/app/models/asset.rb b/app/models/asset.rb
index ff78b324e..77470189a 100644
--- a/app/models/asset.rb
+++ b/app/models/asset.rb
@@ -203,16 +203,30 @@ class Asset < ApplicationRecord
     end
   end
 
+  def previewable?
+    previewable_document? || previewable_image?
+  end
+
   def medium_preview
-    file.variant(resize: Constants::MEDIUM_PIC_FORMAT)
+    return file.variant(resize: Constants::MEDIUM_PIC_FORMAT) if previewable_image?
+
+    'medium/processing.gif'
+    # file.preview(resize: Constants::MEDIUM_PIC_FORMAT)
   end
 
   def large_preview
-    file.variant(resize: Constants::LARGE_PIC_FORMAT)
+    return file.variant(resize: Constants::LARGE_PIC_FORMAT) if previewable_image?
+
+    'large/processing.gif'
+    # file.preview(resize: Constants::LARGE_PIC_FORMAT)
+  end
+
+  def file_name
+    file.blob&.filename&.to_s
   end
 
   def file_size
-    file.blob.byte_size
+    file.blob&.byte_size
   end
 
   def extract_image_quality
@@ -227,13 +241,8 @@ class Asset < ApplicationRecord
     Rails.logger.info "There was an error extracting image quality - #{e}"
   end
 
-  def previewable?
-    file.previewable_image? || file.previewable_document?
-  end
-
-  def is_image?
-    %r{^image/#{Regexp.union(Constants::WHITELISTED_IMAGE_TYPES)}} ===
-      file.content_type
+  def image?
+    file.blob.content_type == %r{^image/#{Regexp.union(Constants::WHITELISTED_IMAGE_TYPES)}}
   end
 
   def text?
@@ -520,6 +529,29 @@ class Asset < ApplicationRecord
 
   private
 
+  def previewable_document?
+    previewable = Constants::PREVIEWABLE_FILE_TYPES.include?(file.blob&.content_type)
+
+    filename = file.blob&.filename
+    content_type = file.blob&.content_type
+
+    extensions = %w(.xlsx .docx .pptx .xls .doc .ppt)
+    # Mimetype sometimes recognizes Office files as zip files
+    # In this case we also check the extension of the given file
+    # Otherwise the conversion should fail if the file is being something else
+    previewable ||= (content_type == 'application/zip' && extensions.include?(File.extname(filename)))
+
+    # Mimetype also sometimes recognizes '.xls' and '.ppt' files as
+    # application/x-ole-storage (https://github.com/minad/mimemagic/issues/50)
+    previewable ||= (content_type == 'application/x-ole-storage' && %w(.xls .ppt).include?(File.extname(filename)))
+
+    previewable
+  end
+
+  def previewable_image?
+    file.blob&.content_type =~ %r{^image/#{Regexp.union(Constants::WHITELISTED_IMAGE_TYPES)}}
+  end
+
   def filter_paperclip_errors
     if errors.size > 1
       temp_errors = errors[:file]
diff --git a/app/models/protocol.rb b/app/models/protocol.rb
index 2e857e14a..add6f26d4 100644
--- a/app/models/protocol.rb
+++ b/app/models/protocol.rb
@@ -236,7 +236,7 @@ class Protocol < ApplicationRecord
       dest.file = src.file
       dest.save!
 
-      if dest.is_image?
+      if dest.image?
         dest.file.reprocess!(:large)
         dest.file.reprocess!(:medium)
       end
@@ -325,7 +325,7 @@ class Protocol < ApplicationRecord
         asset2.created_by = current_user
         asset2.team = dest.team
         asset2.last_modified_by = current_user
-        asset2.file_processing = true if asset.is_image?
+        asset2.file_processing = true if asset.image?
         asset2.save!
 
         step2.assets << asset2
diff --git a/app/services/repository_actions/duplicate_cell.rb b/app/services/repository_actions/duplicate_cell.rb
index c6a8478dc..554638226 100644
--- a/app/services/repository_actions/duplicate_cell.rb
+++ b/app/services/repository_actions/duplicate_cell.rb
@@ -77,13 +77,13 @@ module RepositoryActions
       new_asset.created_by = old_asset.created_by
       new_asset.team = @team
       new_asset.last_modified_by = @user
-      new_asset.file_processing = true if old_asset.is_image?
+      new_asset.file_processing = true if old_asset.image?
       new_asset.file = old_asset.file
       new_asset.save
 
       return unless new_asset.valid?
 
-      if new_asset.is_image?
+      if new_asset.image?
         new_asset.file.reprocess!(:large)
         new_asset.file.reprocess!(:medium)
       end
diff --git a/app/views/my_modules/archive/_result.html.erb b/app/views/my_modules/archive/_result.html.erb
index 51b70b1da..64cc1d1aa 100644
--- a/app/views/my_modules/archive/_result.html.erb
+++ b/app/views/my_modules/archive/_result.html.erb
@@ -36,7 +36,7 @@
   <div class="panel-heading">
     <h3 class="panel-title">
       <% if result.is_asset %>
-        <% if result.asset.is_image? %>
+        <% if result.asset.image? %>
           <span class="fas fa-paperclip"></span>
         <% else %>
           <span class="fas fa-paperclip"></span>
diff --git a/app/views/reports/elements/_my_module_result_asset_element.html.erb b/app/views/reports/elements/_my_module_result_asset_element.html.erb
index ca24d4f9a..3cbb13b6e 100644
--- a/app/views/reports/elements/_my_module_result_asset_element.html.erb
+++ b/app/views/reports/elements/_my_module_result_asset_element.html.erb
@@ -1,6 +1,6 @@
 <% result ||= @result %>
 <% asset = result.asset %>
-<% is_image = result.asset.is_image? %>
+<% is_image = result.asset.image? %>
 <% comments = result.result_comments %>
 <% timestamp = asset.created_at %>
 <% icon_class = 'fas ' + (is_image ? 'fa-image' : 'fa-file') %>
diff --git a/app/views/reports/elements/_step_asset_element.html.erb b/app/views/reports/elements/_step_asset_element.html.erb
index f9bbcde53..b84d9a61b 100644
--- a/app/views/reports/elements/_step_asset_element.html.erb
+++ b/app/views/reports/elements/_step_asset_element.html.erb
@@ -1,5 +1,5 @@
 <% asset ||= @asset %>
-<% is_image = asset.is_image? %>
+<% is_image = asset.image? %>
 <% timestamp = asset.created_at %>
 <% icon_class = 'fas ' + (is_image ? 'fa-image' : 'fa-file') %>
 <div class="report-element report-step-attachment-element report-step-asset-element" data-ts="<%= timestamp.to_i %>" data-type="step_asset" data-id='{ "asset_id": <%= asset.id %> }' data-scroll-id="<%= asset.id %>" data-name="<%=t "projects.reports.elements.step_asset.sidebar_name", file: asset.file_file_name %>" data-icon-class="<%= icon_class %>">
diff --git a/app/views/search/results/_assets.html.erb b/app/views/search/results/_assets.html.erb
index 73a884c4e..68b42a216 100644
--- a/app/views/search/results/_assets.html.erb
+++ b/app/views/search/results/_assets.html.erb
@@ -1,6 +1,6 @@
 <% @asset_results.each do |asset| %>
   <h5>
-    <% if asset.is_image? %>
+    <% if asset.image? %>
       <span class="fas fa-paperclip"></span>
     <% else %>
       <% if wopi_file?(asset) %>
diff --git a/app/views/search/results/_results.html.erb b/app/views/search/results/_results.html.erb
index 4f2849096..a062ba182 100644
--- a/app/views/search/results/_results.html.erb
+++ b/app/views/search/results/_results.html.erb
@@ -5,7 +5,7 @@
     <% elsif result.is_table %>
       <span class="fas fa-table"></span>
     <% else %>
-      <% if result.asset.is_image? %>
+      <% if result.asset.image? %>
         <span class="fas fa-paperclip"></span>
       <% else %>
         <span class="fas fa-paperclip"></span>
diff --git a/app/views/shared/_asset_link.html.erb b/app/views/shared/_asset_link.html.erb
index 7dbd2482f..f214ed94f 100644
--- a/app/views/shared/_asset_link.html.erb
+++ b/app/views/shared/_asset_link.html.erb
@@ -1,37 +1,19 @@
-<% if asset.file_present %>
-  <% if asset.file.processing? && display_image_tag && asset.is_image? %>
-    <span data-status='asset-loading'
-          data-present-url='<%= file_present_asset_path(asset.id) %>'>
-      <%= image_tag 'medium/processing.gif' %>
-      <%= link_to download_asset_path(asset),
-        class: 'file-preview-link',
-        id: "modal_link#{asset.id}",
-        data: { no_turbolink: true, id: true, status: 'asset-present', 'preview-url': asset_file_preview_path(asset) } do %>
-        <span><%= truncate(asset.file_file_name,
-                        length: Constants::FILENAME_TRUNCATION_LENGTH) %></span>
-      <% end %>
-    </span>
-  <% else %>
-    <%= link_to download_asset_path(asset),
-      class: 'file-preview-link',
-      id: "modal_link#{asset.id}",
-      data: { no_turbolink: true, id: true, status: 'asset-present', 'preview-url': asset_file_preview_path(asset) } do %>
-      <% if asset.is_image? && display_image_tag %>
-        <%= image_tag asset.url(:medium) %>
-      <% end %>
-      <% if display_image_tag %>
-        <p>
-          <%= truncate(asset.file_file_name,
-                       length: Constants::FILENAME_TRUNCATION_LENGTH) %>
-        </p>
-        <% else %>
-          <span>
-            <%= truncate(asset.file_file_name,
-                         length: Constants::FILENAME_TRUNCATION_LENGTH) %>
-          </span>
-      <% end %>
-    <% end %>
+<%= link_to download_asset_path(asset),
+  class: 'file-preview-link',
+  id: "modal_link#{asset.id}",
+  data: { no_turbolink: true, id: true, status: 'asset-present', 'preview-url': asset_file_preview_path(asset) } do %>
+  <% if asset.image? && display_image_tag %>
+    <%= image_tag asset.medium_preview %>
+  <% end %>
+  <% if display_image_tag %>
+    <p>
+      <%= truncate(asset.file_file_name,
+                   length: Constants::FILENAME_TRUNCATION_LENGTH) %>
+    </p>
+    <% else %>
+      <span>
+        <%= truncate(asset.file_file_name,
+                     length: Constants::FILENAME_TRUNCATION_LENGTH) %>
+      </span>
   <% end %>
-<% else %>
-  <%= image_tag 'medium/processing.gif' %>
 <% end %>
diff --git a/app/views/shared/_file_preview_icon.html.erb b/app/views/shared/_file_preview_icon.html.erb
index a37b5e60e..45c362022 100644
--- a/app/views/shared/_file_preview_icon.html.erb
+++ b/app/views/shared/_file_preview_icon.html.erb
@@ -1,6 +1,6 @@
 <div>
   <% if asset.file.previewable_document? %>
-    <%= image_tag(asset.url(:large)) %>
+    <%= image_tag(asset.large_preview) %>
   <% else %>
     <i class="fas fa-10x <%= file_fa_icon_class(asset) %>"></i>
   <% end %>
diff --git a/app/views/steps/attachments/_item.html.erb b/app/views/steps/attachments/_item.html.erb
index 08c1be4b3..679f4dafa 100644
--- a/app/views/steps/attachments/_item.html.erb
+++ b/app/views/steps/attachments/_item.html.erb
@@ -1,19 +1,9 @@
-<% if asset.file.processing? && (asset.is_image? || asset.file.previewable_document?) %>
-  <% asset_status = 'asset-loading' %>
-  <% present_url = step_file_present_asset_path(asset.id) %>
-<% else %>
-  <% asset_status = 'asset-present' %>
-  <% present_url = '' %>
-<% end %>
-
 <div class="pseudo-attachment-container" style="order: <%= assets_count - i %>">
     <%= link_to download_asset_path(asset),
             class: 'file-preview-link',
             id: "modal_link#{asset.id}",
             data: { no_turbolink: true,
                     id: true,
-                    status: asset_status,
-                    'present-url': present_url,
                     'preview-url': asset_file_preview_path(asset),
                     'order-atoz': az_ordered_assets_index(step, asset.id),
                     'order-ztoa': assets_count - az_ordered_assets_index(step, asset.id),
diff --git a/app/views/steps/attachments/_placeholder.html.erb b/app/views/steps/attachments/_placeholder.html.erb
index c5c079c52..a07e47d10 100644
--- a/app/views/steps/attachments/_placeholder.html.erb
+++ b/app/views/steps/attachments/_placeholder.html.erb
@@ -1,23 +1,22 @@
-<% image_preview = (asset.is_image? || asset.file.previewable_document?) ? asset.url(:medium) : nil %>
-
 <div class="attachment-placeholder pull-left">
-  <div class="attachment-thumbnail <%= image_preview ? '' : 'no-shadow' %>">
-    <% if image_preview %>
-      <%= image_tag image_preview %>
+  <div class="attachment-thumbnail <%= asset.previewable? ? '' : 'no-shadow' %>">
+    <% if asset.previewable? %>
+      <%= image_tag asset.medium_preview %>
     <% else %>
-      <i class="fas <%= file_fa_icon_class(asset) if asset.file_file_name %>"></i>
+      <i class="fas <%= file_fa_icon_class(asset) if asset.file_name %>"></i>
     <% end %>
   </div>
-  <div class="attachment-label"><%= truncate(asset.file_file_name,
-                                             length: Constants::FILENAME_TRUNCATION_LENGTH) %></div>
+  <div class="attachment-label">
+    <%= truncate(asset.file_name, length: Constants::FILENAME_TRUNCATION_LENGTH) %>
+  </div>
   <div class="spencer-bonnet-modif">
     <%= t('protocols.steps.attachments.modified_label') %> <%= l(asset.updated_at, format: :full_date) if asset.updated_at %>  <br>
-    <%= number_to_human_size(asset.file.size) %>
+    <%= number_to_human_size(asset.file_size) %>
   </div>
 
   <% if edit_page %>
     <div class="remove-icon pull-right">
-      <% unless ff.object.file.exists? && ff.object.locked? %>
+      <% unless ff.object.file.attached? && ff.object.locked? %>
         <%= ff.remove_nested_fields_link do %>
           <span class="fas fa-trash"></span>
         <% end %>
diff --git a/config/initializers/paperclip.rb b/config/initializers/paperclip.rb
index 7ac23bbe9..f032d32ca 100644
--- a/config/initializers/paperclip.rb
+++ b/config/initializers/paperclip.rb
@@ -61,27 +61,6 @@ Paperclip::Attachment.class_eval do
   def fetch
     Paperclip.io_adapters.for self
   end
-
-  def previewable_document?
-    previewable = Constants::PREVIEWABLE_FILE_TYPES.include?(content_type)
-
-    extensions = %w(.xlsx .docx .pptx .xls .doc .ppt)
-    # Mimetype sometimes recognizes Office files as zip files
-    # In this case we also check the extension of the given file
-    # Otherwise the conversion should fail if the file is being something else
-    previewable ||= (content_type == 'application/zip' && extensions.include?(File.extname(original_filename)))
-
-    # Mimetype also sometimes recognizes '.xls' and '.ppt' files as
-    # application/x-ole-storage (https://github.com/minad/mimemagic/issues/50)
-    previewable ||=
-      (content_type == 'application/x-ole-storage' && %w(.xls .ppt).include?(File.extname(original_filename)))
-
-    previewable
-  end
-
-  def previewable_image?
-    content_type =~ %r{^image/#{Regexp.union(Constants::WHITELISTED_IMAGE_TYPES)}}
-  end
 end
 
 module Paperclip
diff --git a/db/migrate/20190613134100_convert_to_active_storage.rb b/db/migrate/20190613134100_convert_to_active_storage.rb
index ea9de35b3..76593aa1b 100644
--- a/db/migrate/20190613134100_convert_to_active_storage.rb
+++ b/db/migrate/20190613134100_convert_to_active_storage.rb
@@ -41,7 +41,7 @@ class ConvertToActiveStorage < ActiveRecord::Migration[5.2]
                 instance.__send__("#{attachment}_file_name"),
                 instance.__send__("#{attachment}_content_type"),
                 instance.__send__("#{attachment}_file_size") || 0,
-                checksum(instance.__send__(attachment)),
+                checksum(attachment),
                 instance.updated_at.iso8601
               ]
             )
@@ -96,12 +96,12 @@ class ConvertToActiveStorage < ActiveRecord::Migration[5.2]
   def key(instance, attachment)
     # SecureRandom.uuid
     # Alternatively:
-    pattern = if ENV['PAPERCLIP_STORAGE'] == 's3'
-                ':class/:attachment/:id_partition/:hash/original/:filename'
-              else
-                "#{Rails.root}/public/system/:class/:attachment/:id_partition/:hash/original/:filename"
-              end
-    interpolate(pattern, instance, attachment)
+    if ENV['PAPERCLIP_STORAGE'] == 's3'
+      interpolate(':class/:attachment/:id_partition/:hash/original/:filename', instance, attachment)
+    else
+      key = SecureRandom.uuid
+      File.join('storage', key.first(2), key.first(4).last(2))
+    end
   end
 
   def checksum(_attachment)
diff --git a/lib/tasks/paperclip.rake b/lib/tasks/paperclip.rake
index eea765620..21c79a6e3 100644
--- a/lib/tasks/paperclip.rake
+++ b/lib/tasks/paperclip.rake
@@ -36,7 +36,7 @@ namespace :paperclip do
       assets = assets.where('updated_at < ?', eval(args[:before]))
     end
     assets.find_each(batch_size: 100) do |asset|
-      next unless asset.is_image?
+      next unless asset.image?
       begin
         asset.file.reprocess! :medium, :large
       rescue