diff --git a/app/controllers/iqdb_queries_controller.rb b/app/controllers/iqdb_queries_controller.rb
index 2e89db0d4..9e77438cf 100644
--- a/app/controllers/iqdb_queries_controller.rb
+++ b/app/controllers/iqdb_queries_controller.rb
@@ -5,7 +5,7 @@ class IqdbQueriesController < ApplicationController
 
   def show
     # XXX allow bare search params for backwards compatibility.
-    search_params.merge!(params.slice(:url, :hash, :image_url, :file_url, :post_id, :limit, :similarity, :high_similarity).permit!)
+    search_params.merge!(params.slice(:url, :hash, :image_url, :file_url, :post_id, :media_asset_id, :limit, :similarity, :high_similarity).permit!)
 
     iqdb_params = search_params.to_h.symbolize_keys
     @high_similarity_matches, @low_similarity_matches, @matches = IqdbClient.new.search(**iqdb_params)
diff --git a/app/javascript/src/javascripts/uploads.js b/app/javascript/src/javascripts/uploads.js
index 5d34a8e1c..87de7422e 100644
--- a/app/javascript/src/javascripts/uploads.js
+++ b/app/javascript/src/javascripts/uploads.js
@@ -26,18 +26,16 @@ Upload.initialize_all = function() {
 }
 
 Upload.initialize_similar = function() {
-  let source = $("#post_source").val();
+  let media_asset_id = $("input[name='post[media_asset_id]']").val();
 
-  if (/^https?:\/\//.test(source)) {
-    $.get("/iqdb_queries.js", {
-      limit: Upload.IQDB_LIMIT,
-      search: {
-        url: source,
-        similarity: Upload.IQDB_MIN_SIMILARITY,
-        high_similarity: Upload.IQDB_HIGH_SIMILARITY
-      }
-    });
-  }
+  $.get("/iqdb_queries.js", {
+    limit: Upload.IQDB_LIMIT,
+    search: {
+      media_asset_id: media_asset_id,
+      similarity: Upload.IQDB_MIN_SIMILARITY,
+      high_similarity: Upload.IQDB_HIGH_SIMILARITY
+    }
+  });
 }
 
 Upload.initialize_image = function() {
diff --git a/app/logical/iqdb_client.rb b/app/logical/iqdb_client.rb
index dc11d3d92..b4e8a45c7 100644
--- a/app/logical/iqdb_client.rb
+++ b/app/logical/iqdb_client.rb
@@ -18,7 +18,7 @@ class IqdbClient
 
   concerning :QueryMethods do
     # Search for an image by file, URL, hash, or post ID.
-    def search(post_id: nil, file: nil, hash: nil, url: nil, image_url: nil, file_url: nil, similarity: 0.0, high_similarity: 65.0, limit: 20)
+    def search(post_id: nil, media_asset_id: nil, file: nil, hash: nil, url: nil, image_url: nil, file_url: nil, similarity: 0.0, high_similarity: 65.0, limit: 20)
       limit = limit.to_i.clamp(1, 1000)
       similarity = similarity.to_f.clamp(0.0, 100.0)
       high_similarity = high_similarity.to_f.clamp(0.0, 100.0)
@@ -33,6 +33,8 @@ class IqdbClient
         file = download(file_url, :image_url)
       elsif post_id.present?
         file = Post.find(post_id).file(:preview)
+      elsif media_asset_id.present?
+        file = MediaAsset.find(media_asset_id).variant("360x360").open_file
       end
 
       if hash.present?
diff --git a/app/models/upload.rb b/app/models/upload.rb
index 654f37ac5..bb1d5ffa1 100644
--- a/app/models/upload.rb
+++ b/app/models/upload.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Upload < ApplicationRecord
+  extend Memoist
+
   MAX_VIDEO_DURATION = 140
 
   attr_accessor :file
@@ -76,7 +78,14 @@ class Upload < ApplicationRecord
     raise
   end
 
+  def source_strategy
+    return nil if source.blank?
+    Sources::Strategies.find(source, referer_url)
+  end
+
   def self.available_includes
     [:uploader, :upload_media_assets, :media_assets]
   end
+
+  memoize :source_strategy
 end
diff --git a/app/policies/post_policy.rb b/app/policies/post_policy.rb
index 84f596771..aa498d77c 100644
--- a/app/policies/post_policy.rb
+++ b/app/policies/post_policy.rb
@@ -71,9 +71,9 @@ class PostPolicy < ApplicationPolicy
   end
 
   def permitted_attributes_for_create
-    %i[upload_media_asset_id tag_string rating parent_id source is_pending
-    artist_commentary_desc artist_commentary_title translated_commentary_desc
-    translated_commentary_title]
+    %i[upload_id media_asset_id upload_media_asset_id tag_string rating
+    parent_id source is_pending artist_commentary_desc artist_commentary_title
+    translated_commentary_desc translated_commentary_title]
   end
 
   def permitted_attributes_for_update
diff --git a/app/views/uploads/_related_posts.html.erb b/app/views/uploads/_related_posts.html.erb
index 4a9c3e3e8..b62377377 100644
--- a/app/views/uploads/_related_posts.html.erb
+++ b/app/views/uploads/_related_posts.html.erb
@@ -16,12 +16,4 @@
   </div>
 <% end %>
 
-<% if Danbooru.config.iqdb_url %>
-  <% if params[:url] %>
-    <div class="input" id="iqdb-similar">
-      <p><em>Loading similar...</em></p>
-    </div>
-  <% else %>
-    <div class="input" id="iqdb-similar" style="display: none;"></div>
-  <% end %>
-<% end %>
+<div class="input" id="iqdb-similar" style="display: none;"></div>
diff --git a/app/views/uploads/show.html.erb b/app/views/uploads/show.html.erb
index 9608d3813..02612d334 100644
--- a/app/views/uploads/show.html.erb
+++ b/app/views/uploads/show.html.erb
@@ -45,13 +45,15 @@
         <%= tag.img src: @media_asset.variant("original").file_url, title: "Preview", id: "image", class: "fit-width fit-height", "data-shortcut": "z"  %>
       </div>
 
-      <% if @upload.source.present? %>
-        <% @source = ::Sources::Strategies.find(@upload.source, @upload.referer_url) %>
-        <%= render "uploads/related_posts", source: @source %>
-        <%= render_source_data(@source) %>
+      <%= render "uploads/related_posts", source: @upload.source_strategy %>
+
+      <% if @upload.source_strategy.present? %>
+        <%= render_source_data(@upload.source_strategy) %>
       <% end %>
 
       <%= edit_form_for(@post, html: { id: "form" }) do |f| %>
+        <%= f.input :upload_id, as: :hidden, input_html: { value: @upload.id } %>
+        <%= f.input :media_asset_id, as: :hidden, input_html: { value: @media_asset.id } %>
         <%= f.input :upload_media_asset_id, as: :hidden, input_html: { value: @upload_media_asset.id } %>
 
         <%= f.input :source, as: :string %>