diff --git a/app/logical/media_file.rb b/app/logical/media_file.rb
index d7991c61b..ac4dd8bcd 100644
--- a/app/logical/media_file.rb
+++ b/app/logical/media_file.rb
@@ -19,6 +19,8 @@ class MediaFile
   # @param options [Hash] extra options for the MediaFile subclass.
   # @return [MediaFile] the media file
   def self.open(file, **options)
+    return file.dup if file.is_a?(MediaFile)
+
     file = Kernel.open(file, "r", binmode: true) unless file.respond_to?(:read)
 
     case file_ext(file)
diff --git a/app/logical/media_file/ugoira.rb b/app/logical/media_file/ugoira.rb
index 893457731..cfd765131 100644
--- a/app/logical/media_file/ugoira.rb
+++ b/app/logical/media_file/ugoira.rb
@@ -7,7 +7,7 @@
 # zip file, so it must be passed around separately.
 class MediaFile::Ugoira < MediaFile
   class Error < StandardError; end
-  attr_reader :frame_data
+  attr_accessor :frame_data
 
   def initialize(file, frame_data: {}, **options)
     super(file, **options)
diff --git a/app/logical/sources/strategies/base.rb b/app/logical/sources/strategies/base.rb
index 89ec4124f..6fe42e0aa 100644
--- a/app/logical/sources/strategies/base.rb
+++ b/app/logical/sources/strategies/base.rb
@@ -276,10 +276,6 @@ module Sources
         image_url
       end
 
-      def data
-        {}
-      end
-
       def tags
         (@tags || []).uniq
       end
diff --git a/app/logical/sources/strategies/pixiv.rb b/app/logical/sources/strategies/pixiv.rb
index fb80f8e6b..af7650438 100644
--- a/app/logical/sources/strategies/pixiv.rb
+++ b/app/logical/sources/strategies/pixiv.rb
@@ -199,6 +199,12 @@ module Sources
         tag.gsub(/\d+users入り\z/i, "")
       end
 
+      def download_file!(url = image_url)
+        file = super(url)
+        file.frame_data = ugoira_frame_data if is_ugoira?
+        file
+      end
+
       def translate_tag(tag)
         translated_tags = super(tag)
 
@@ -297,8 +303,9 @@ module Sources
         end
       end
 
-      def data
-        { ugoira_frame_data: api_ugoira[:frames] }
+      def ugoira_frame_data
+        return nil unless is_ugoira?
+        api_ugoira[:frames]
       end
 
       def ugoira_content_type
diff --git a/app/logical/upload_service.rb b/app/logical/upload_service.rb
index 12e95d90f..9e694cd64 100644
--- a/app/logical/upload_service.rb
+++ b/app/logical/upload_service.rb
@@ -43,7 +43,7 @@ class UploadService
 
       @upload.update(status: "processing")
 
-      @upload.file = Utils.get_file_for_upload(@upload, file: @upload.file&.tempfile)
+      @upload.file = Utils.get_file_for_upload(@upload.source_url, @upload.referer_url, @upload.file&.tempfile)
       Utils.process_file(upload, @upload.file)
 
       @upload.save!
@@ -64,14 +64,6 @@ class UploadService
     @post = convert_to_post(upload)
     @post.save!
 
-    if upload.context && upload.context["ugoira"]
-      PixivUgoiraFrameData.create(
-        post_id: @post.id,
-        data: upload.context["ugoira"]["frame_data"],
-        content_type: upload.context["ugoira"]["content_type"]
-      )
-    end
-
     if upload.has_commentary?
       @post.create_artist_commentary(
         :original_title => upload.artist_commentary_title,
diff --git a/app/logical/upload_service/preprocessor.rb b/app/logical/upload_service/preprocessor.rb
index f8b298e17..a90444df5 100644
--- a/app/logical/upload_service/preprocessor.rb
+++ b/app/logical/upload_service/preprocessor.rb
@@ -71,7 +71,7 @@ class UploadService
       begin
         upload.update(status: "preprocessing")
 
-        file = Utils.get_file_for_upload(upload, file: params[:file]&.tempfile)
+        file = Utils.get_file_for_upload(upload.source_url, upload.referer_url, params[:file]&.tempfile)
         Utils.process_file(upload, file, original_post_id: original_post_id)
 
         upload.rating = params[:rating]
diff --git a/app/logical/upload_service/replacer.rb b/app/logical/upload_service/replacer.rb
index 739d7c161..684c032e9 100644
--- a/app/logical/upload_service/replacer.rb
+++ b/app/logical/upload_service/replacer.rb
@@ -61,69 +61,44 @@ class UploadService
       undoer.process!
     end
 
-    def source_strategy(upload)
-      Sources::Strategies.find(upload.source, upload.referer_url)
-    end
-
-    def find_replacement_url(repl, upload)
-      if repl.replacement_file.present?
-        return "file://#{repl.replacement_file.original_filename}"
+    def replacement_url
+      if replacement.replacement_file.present?
+        "file://#{replacement.replacement_file.original_filename}"
+      else
+        Sources::Strategies.find(replacement.replacement_url).canonical_url
       end
-
-      if upload.source.blank?
-        raise "No source found in upload for replacement"
-      end
-
-      if source_strategy(upload).canonical_url.present?
-        return source_strategy(upload).canonical_url
-      end
-
-      upload.source
     end
 
     def process!
-      preprocessor = Preprocessor.new(
-        rating: post.rating,
-        tag_string: replacement.tags,
-        source: replacement.replacement_url,
-        file: replacement.replacement_file,
-        replaced_post: post,
-        original_post_id: post.id
-      )
-      upload = preprocessor.start!
-      raise Error, upload.status if upload.is_errored?
-      upload = preprocessor.finish!(upload)
-      raise Error, upload.status if upload.is_errored?
-      md5_changed = upload.md5 != post.md5
+      media_file = Utils::get_file_for_upload(replacement.replacement_url, nil, replacement.replacement_file&.tempfile)
 
-      replacement.replacement_url = find_replacement_url(replacement, upload)
-
-      if md5_changed
-        post.queue_delete_files(PostReplacement::DELETION_GRACE_PERIOD)
+      if media_file.md5 == post.md5
+        raise Error, "Can't replace a post with itself; regenerate the post instead"
+      elsif Post.exists?(md5: media_file.md5)
+        raise Error, "Duplicate: post with md5 #{media_file.md5} already exists"
       end
 
-      replacement.file_ext = upload.file_ext
-      replacement.file_size = upload.file_size
-      replacement.image_height = upload.image_height
-      replacement.image_width = upload.image_width
-      replacement.md5 = upload.md5
+      media_asset = MediaAsset.upload!(media_file)
+      post.queue_delete_files(PostReplacement::DELETION_GRACE_PERIOD)
 
-      post.md5 = upload.md5
-      post.file_ext = upload.file_ext
-      post.image_width = upload.image_width
-      post.image_height = upload.image_height
-      post.file_size = upload.file_size
+      replacement.replacement_url = replacement_url
+      replacement.file_ext = media_asset.file_ext
+      replacement.file_size = media_asset.file_size
+      replacement.image_height = media_asset.image_height
+      replacement.image_width = media_asset.image_width
+      replacement.md5 = media_asset.md5
+
+      post.md5 = media_asset.md5
+      post.file_ext = media_asset.file_ext
+      post.image_width = media_asset.image_width
+      post.image_height = media_asset.image_height
+      post.file_size = media_asset.file_size
       post.source = replacement.final_source.presence || replacement.replacement_url
-      post.tag_string = upload.tag_string
+      post.tag_string = replacement.tags
 
       rescale_notes(post)
-      update_ugoira_frame_data(post, upload)
 
-      if md5_changed
-        CurrentUser.scoped(User.system) { Comment.create!(post: post, creator: User.system, updater: User.system, body: comment_replacement_message(post, replacement), do_not_bump_post: true, creator_ip_addr: "127.0.0.1") }
-      else
-        purge_cached_urls(post)
-      end
+      CurrentUser.scoped(User.system) { Comment.create!(post: post, creator: User.system, updater: User.system, body: comment_replacement_message(post, replacement), do_not_bump_post: true, creator_ip_addr: "127.0.0.1") }
 
       replacement.save!
       post.save!
@@ -131,18 +106,6 @@ class UploadService
       post.update_iqdb
     end
 
-    def purge_cached_urls(post)
-      urls = [
-        post.preview_file_url,
-        post.large_file_url,
-        post.file_url,
-        post.tagged_large_file_url,
-        post.tagged_file_url
-      ]
-
-      CloudflareService.new.purge_cache(urls)
-    end
-
     def rescale_notes(post)
       x_scale = post.image_width.to_f  / post.image_width_was.to_f
       y_scale = post.image_height.to_f / post.image_height_was.to_f
@@ -151,19 +114,5 @@ class UploadService
         note.rescale!(x_scale, y_scale)
       end
     end
-
-    def update_ugoira_frame_data(post, upload)
-      post.pixiv_ugoira_frame_data.destroy if post.pixiv_ugoira_frame_data.present?
-
-      unless post.is_ugoira?
-        return
-      end
-
-      PixivUgoiraFrameData.create(
-        post_id: post.id,
-        data: upload.context["ugoira"]["frame_data"],
-        content_type: upload.context["ugoira"]["content_type"]
-      )
-    end
   end
 end
diff --git a/app/logical/upload_service/utils.rb b/app/logical/upload_service/utils.rb
index ed23c8fc9..f5a219706 100644
--- a/app/logical/upload_service/utils.rb
+++ b/app/logical/upload_service/utils.rb
@@ -7,9 +7,9 @@ class UploadService
     end
 
     def process_file(upload, file, original_post_id: nil)
-      upload.file = file
-      media_file = upload.media_file
+      media_file = MediaFile.open(file)
 
+      upload.file = media_file
       upload.file_ext = media_file.file_ext.to_s
       upload.file_size = media_file.file_size
       upload.md5 = media_file.md5
@@ -28,25 +28,14 @@ class UploadService
       tags.join(" ")
     end
 
-    def get_file_for_upload(upload, file: nil)
-      return file if file.present?
-      raise "No file or source URL provided" if upload.source_url.blank?
+    def get_file_for_upload(source_url, referer_url, file)
+      return MediaFile.open(file) if file.present?
+      raise "No file or source URL provided" if source_url.blank?
 
-      strategy = Sources::Strategies.find(upload.source_url, upload.referer_url)
+      strategy = Sources::Strategies.find(source_url, referer_url)
       raise NotImplementedError, "No login credentials configured for #{strategy.site_name}." unless strategy.class.enabled?
 
-      file = strategy.download_file!
-
-      if strategy.data[:ugoira_frame_data].present?
-        upload.context = {
-          "ugoira" => {
-            "frame_data" => strategy.data[:ugoira_frame_data],
-            "content_type" => "image/jpeg"
-          }
-        }
-      end
-
-      file
+      strategy.download_file!
     end
   end
 end
diff --git a/app/models/media_asset.rb b/app/models/media_asset.rb
index dff00ebf1..3be6214e5 100644
--- a/app/models/media_asset.rb
+++ b/app/models/media_asset.rb
@@ -1,5 +1,7 @@
 class MediaAsset < ApplicationRecord
   has_one :media_metadata, dependent: :destroy
+  has_one :pixiv_ugoira_frame_data, class_name: "PixivUgoiraFrameData", dependent: :destroy, foreign_key: :md5, primary_key: :md5
+
   delegate :metadata, to: :media_metadata
   delegate :is_non_repeating_animation?, :is_greyscale?, :is_rotated?, to: :metadata
 
@@ -136,6 +138,7 @@ class MediaAsset < ApplicationRecord
       self.image_height = media_file.height
       self.duration = media_file.duration
       self.media_metadata = MediaMetadata.new(file: media_file)
+      self.pixiv_ugoira_frame_data = PixivUgoiraFrameData.new(data: media_file.frame_data, content_type: "image/jpeg") if is_ugoira?
     end
 
     def delete_files!
diff --git a/app/models/pixiv_ugoira_frame_data.rb b/app/models/pixiv_ugoira_frame_data.rb
index bbb5a5498..89b7d97b0 100644
--- a/app/models/pixiv_ugoira_frame_data.rb
+++ b/app/models/pixiv_ugoira_frame_data.rb
@@ -1,5 +1,6 @@
 class PixivUgoiraFrameData < ApplicationRecord
-  belongs_to :post
+  belongs_to :post, optional: true, foreign_key: :md5, primary_key: :md5
+  belongs_to :media_asset, foreign_key: :md5, primary_key: :md5
 
   serialize :data
   before_validation :normalize_data, on: :create
@@ -9,7 +10,7 @@ class PixivUgoiraFrameData < ApplicationRecord
   end
 
   def self.search(params)
-    q = search_attributes(params, :id, :data, :content_type, :post)
+    q = search_attributes(params, :id, :data, :content_type, :post, :md5)
     q.apply_default_order(params)
   end
 
diff --git a/app/models/post.rb b/app/models/post.rb
index d1e11e3f5..e32ea6e4a 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -40,7 +40,7 @@ class Post < ApplicationRecord
   has_one :media_asset, foreign_key: :md5, primary_key: :md5
   has_one :upload, :dependent => :destroy
   has_one :artist_commentary, :dependent => :destroy
-  has_one :pixiv_ugoira_frame_data, :class_name => "PixivUgoiraFrameData", :dependent => :destroy
+  has_one :pixiv_ugoira_frame_data, class_name: "PixivUgoiraFrameData", foreign_key: :md5, primary_key: :md5
   has_many :flags, :class_name => "PostFlag", :dependent => :destroy
   has_many :appeals, :class_name => "PostAppeal", :dependent => :destroy
   has_many :votes, :class_name => "PostVote", :dependent => :destroy
diff --git a/app/models/upload.rb b/app/models/upload.rb
index 665dacbd5..12d636f65 100644
--- a/app/models/upload.rb
+++ b/app/models/upload.rb
@@ -19,7 +19,7 @@ class Upload < ApplicationRecord
     end
 
     def validate_integrity(record)
-      if record.media_file.is_corrupt?
+      if record.file.is_corrupt?
         record.errors.add(:file, "is corrupted")
       end
     end
@@ -55,7 +55,7 @@ class Upload < ApplicationRecord
     end
 
     def validate_video_duration(record)
-      if !record.uploader.is_admin? && record.media_file.is_video? && record.media_file.duration > MAX_VIDEO_DURATION
+      if !record.uploader.is_admin? && record.file.is_video? && record.file.duration > MAX_VIDEO_DURATION
         record.errors.add(:base, "video must not be longer than #{MAX_VIDEO_DURATION.seconds.inspect}")
       end
     end
@@ -105,10 +105,6 @@ class Upload < ApplicationRecord
   end
 
   concerning :FileMethods do
-    def media_file
-      @media_file ||= MediaFile.open(file, frame_data: context.to_h.dig("ugoira", "frame_data"))
-    end
-
     def delete_files
       # md5 is blank if the upload errored out before downloading the file.
       if is_completed? || md5.blank? || Upload.exists?(md5: md5) || Post.exists?(md5: md5)
diff --git a/db/migrate/20211018062916_change_post_id_to_nullable_on_pixiv_ugoira_frame_data.rb b/db/migrate/20211018062916_change_post_id_to_nullable_on_pixiv_ugoira_frame_data.rb
new file mode 100644
index 000000000..0be2470eb
--- /dev/null
+++ b/db/migrate/20211018062916_change_post_id_to_nullable_on_pixiv_ugoira_frame_data.rb
@@ -0,0 +1,5 @@
+class ChangePostIdToNullableOnPixivUgoiraFrameData < ActiveRecord::Migration[6.1]
+  def change
+    change_column_null :pixiv_ugoira_frame_data, :post_id, true
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index 8b8a2443e..318c286e7 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -1327,7 +1327,7 @@ ALTER SEQUENCE public.notes_id_seq OWNED BY public.notes.id;
 
 CREATE TABLE public.pixiv_ugoira_frame_data (
     id integer NOT NULL,
-    post_id integer NOT NULL,
+    post_id integer,
     data text NOT NULL,
     content_type character varying NOT NULL,
     md5 character varying
@@ -5048,6 +5048,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20211013011619'),
 ('20211014063943'),
 ('20211015223510'),
-('20211018045429');
+('20211018045429'),
+('20211018062916');
 
 
diff --git a/test/unit/downloads/pixiv_test.rb b/test/unit/downloads/pixiv_test.rb
index 00248c1d6..f651a77e4 100644
--- a/test/unit/downloads/pixiv_test.rb
+++ b/test/unit/downloads/pixiv_test.rb
@@ -131,9 +131,10 @@ module Downloads
     context "An ugoira site for pixiv" do
       should "capture the data" do
         @strategy = Sources::Strategies.find("http://www.pixiv.net/member_illust.php?mode=medium&illust_id=62247364")
+        media_file = @strategy.download_file!
 
-        assert_equal(2, @strategy.data[:ugoira_frame_data].size)
-        assert_equal([{"file" => "000000.jpg", "delay" => 125}, {"file" => "000001.jpg", "delay" => 125}], @strategy.data[:ugoira_frame_data])
+        assert_equal(2, media_file.frame_data.size)
+        assert_equal([{"file" => "000000.jpg", "delay" => 125}, {"file" => "000001.jpg", "delay" => 125}], media_file.frame_data)
       end
     end
   end
diff --git a/test/unit/sources/pixiv_test.rb b/test/unit/sources/pixiv_test.rb
index 87b89f9d9..146a4292e 100644
--- a/test/unit/sources/pixiv_test.rb
+++ b/test/unit/sources/pixiv_test.rb
@@ -48,10 +48,10 @@ module Sources
         end
 
         should "capture the frame data" do
-          ugoira_frame_data = @site.data[:ugoira_frame_data]
+          media_file = @site.download_file!
 
-          assert_equal(2, ugoira_frame_data.size)
-          assert_equal([{"file" => "000000.jpg", "delay" => 125}, {"file" => "000001.jpg", "delay" => 125}], ugoira_frame_data)
+          assert_equal(2, media_file.frame_data.size)
+          assert_equal([{"file" => "000000.jpg", "delay" => 125}, {"file" => "000001.jpg", "delay" => 125}], media_file.frame_data)
         end
       end
 
diff --git a/test/unit/upload_service_test.rb b/test/unit/upload_service_test.rb
index 56eb59339..aa86d5a80 100644
--- a/test/unit/upload_service_test.rb
+++ b/test/unit/upload_service_test.rb
@@ -23,59 +23,6 @@ class UploadServiceTest < ActiveSupport::TestCase
   end
 
   context "::Utils" do
-    context "#get_file_for_upload" do
-      context "for a non-source site" do
-        setup do
-          @source = "https://upload.wikimedia.org/wikipedia/commons/c/c5/Moraine_Lake_17092005.jpg"
-          @upload = Upload.new
-          @upload.source = @source
-        end
-
-        should "work on a jpeg" do
-          file = UploadService::Utils.get_file_for_upload(@upload)
-          assert_operator(File.size(file.path), :>, 0)
-          file.close
-        end
-      end
-
-      context "for a pixiv" do
-        setup do
-          skip "Pixiv credentials not configured" unless Sources::Strategies::Pixiv.enabled?
-
-          @source = "http://www.pixiv.net/member_illust.php?mode=medium&illust_id=62247350"
-          @upload = Upload.new
-          @upload.source = @source
-        end
-
-        should "work on an ugoira url" do
-          begin
-            file = UploadService::Utils.get_file_for_upload(@upload)
-            assert_operator(File.size(file.path), :>, 0)
-            file.close
-          end
-        end
-      end
-
-      context "for a pixiv ugoira" do
-        setup do
-          skip "Pixiv credentials not configured" unless Sources::Strategies::Pixiv.enabled?
-
-          @source = "https://i.pximg.net/img-zip-ugoira/img/2017/04/04/08/57/38/62247364_ugoira1920x1080.zip"
-          @referer = "http://www.pixiv.net/member_illust.php?mode=medium&illust_id=62247364"
-          @upload = Upload.new
-          @upload.source = @source
-          @upload.referer_url = @referer
-        end
-
-        should "work on an ugoira url" do
-          file = UploadService::Utils.get_file_for_upload(@upload)
-
-          assert_not_nil(@upload.context["ugoira"])
-          assert_operator(File.size(file.path), :>, 0)
-        end
-      end
-    end
-
     context ".process_file" do
       setup do
         @upload = FactoryBot.build(:jpg_upload)
@@ -286,12 +233,6 @@ class UploadServiceTest < ActiveSupport::TestCase
       subject { UploadService::Replacer.new(post: @post, replacement: @replacement) }
 
       context "#process!" do
-        should "create a new upload" do
-          assert_difference(-> { Upload.count }) do
-            as(@user) { subject.process! }
-          end
-        end
-
         should "create a comment" do
           assert_difference(-> { @post.comments.count }) do
             as(@user) { subject.process! }
@@ -342,22 +283,13 @@ class UploadServiceTest < ActiveSupport::TestCase
       end
 
       context "a post with the same file" do
-        should "not raise a duplicate error" do
+        should "raise an error" do
           upload_file("test/files/test.png") do |file|
-            assert_nothing_raised do
+            assert_raises(UploadService::Replacer::Error) do
               as(@user) { @post.replace!(replacement_file: file, replacement_url: "") }
             end
           end
         end
-
-        should "not queue a deletion or log a comment" do
-          upload_file("test/files/test.png") do |file|
-            assert_no_difference(-> { @post.comments.count }) do
-              as(@user) { @post.replace!(replacement_file: file, replacement_url: "") }
-              @post.reload
-            end
-          end
-        end
       end
     end
 
@@ -407,9 +339,10 @@ class UploadServiceTest < ActiveSupport::TestCase
       subject { UploadService::Replacer.new(post: @post, replacement: @replacement) }
 
       context "when replacing with its own source" do
-        should "work" do
-          as(@user) { @post.replace!(replacement_url: @post.source) }
-          assert_equal(@post_md5, @post.md5)
+        should "raise an error" do
+          assert_raises(UploadService::Replacer::Error) do
+            as(@user) { @post.replace!(replacement_url: @post.source) }
+          end
         end
       end
 
@@ -480,12 +413,6 @@ class UploadServiceTest < ActiveSupport::TestCase
       end
 
       context "#process!" do
-        should "create a new upload" do
-          assert_difference(-> { Upload.count }) do
-            as(@user) { subject.process! }
-          end
-        end
-
         should "create a comment" do
           assert_difference(-> { @post.comments.count }) do
             as(@user) { subject.process! }
@@ -911,20 +838,6 @@ class UploadServiceTest < ActiveSupport::TestCase
       end
     end
 
-    context "for a pixiv ugoira" do
-      setup do
-        @upload = FactoryBot.create(:ugoira_upload, file_size: 1000, md5: "12345", file_ext: "jpg", image_width: 100, image_height: 100, context: UGOIRA_CONTEXT)
-      end
-
-      should "create a post" do
-        assert_difference(-> { PixivUgoiraFrameData.count }) do
-          post = subject.new({}).create_post_from_upload(@upload)
-          assert_equal([], post.errors.full_messages)
-          assert_not_nil(post.id)
-        end
-      end
-    end
-
     context "for nijie" do
       should "record the canonical source" do
         page_url = "https://nijie.info/view.php?id=728995"