diff --git a/app/controllers/post_replacements_controller.rb b/app/controllers/post_replacements_controller.rb
index 6b66cffe7..eebbedd81 100644
--- a/app/controllers/post_replacements_controller.rb
+++ b/app/controllers/post_replacements_controller.rb
@@ -14,6 +14,13 @@ class PostReplacementsController < ApplicationController
     respond_with(@post_replacement, location: @post)
   end
 
+  def update
+    @post_replacement = PostReplacement.find(params[:id])
+    @post_replacement.update(update_params)
+
+    respond_with(@post_replacement)
+  end
+
   def index
     params[:search][:post_id] = params.delete(:post_id) if params.has_key?(:post_id)
     @post_replacements = PostReplacement.search(params[:search]).paginate(params[:page], limit: params[:limit])
@@ -25,4 +32,12 @@ private
   def create_params
     params.require(:post_replacement).permit(:replacement_url, :replacement_file, :final_source, :tags)
   end
+
+  def update_params
+    params.require(:post_replacement).permit(
+      :file_ext_was, :file_size_was, :image_width_was, :image_height_was, :md5_was,
+      :file_ext, :file_size, :image_width, :image_height, :md5,
+      :original_url, :replacement_url
+    )
+  end
 end
diff --git a/config/routes.rb b/config/routes.rb
index 9e8e17021..b2d602646 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -195,7 +195,7 @@ Rails.application.routes.draw do
       get :diff
     end
   end
-  resources :post_replacements, :only => [:index, :new, :create]
+  resources :post_replacements, :only => [:index, :new, :create, :update]
   resources :posts do
     resources :events, :only => [:index], :controller => "post_events"
     resources :replacements, :only => [:index, :new, :create], :controller => "post_replacements"
diff --git a/test/functional/post_replacements_controller_test.rb b/test/functional/post_replacements_controller_test.rb
index 84b9399a5..c4d05597e 100644
--- a/test/functional/post_replacements_controller_test.rb
+++ b/test/functional/post_replacements_controller_test.rb
@@ -43,6 +43,25 @@ class PostReplacementsControllerTest < ActionController::TestCase
       end
     end
 
+    context "update action" do
+      should "update the replacement" do
+        params = {
+          format: :json,
+          id: @post_replacement.id,
+          post_replacement: {
+            file_size_was: 23,
+            file_size: 42,
+          }
+        }
+
+        put :update, params, { user_id: @user.id }
+        @post_replacement.reload
+
+        assert_equal(23, @post_replacement.file_size_was)
+        assert_equal(42, @post_replacement.file_size)
+      end
+    end
+
     context "index action" do
       should "render" do
         get :index, {format: :json}