Define #preload_relations on Ingredients

app/models/alchemy/ingredient.rb

@@ -90,6 +90,12 @@ def allowed_settings
       end
     end
 
+    # This method can be overwritten in individual ingredients to fetch objects that belong to the related object in some form.
+    # This takes an Array of things that can be passed to the Rails preloader.
+    def preload_relations
+      []
+    end
+
     # The value or the related object if present
     def value
       related_object || self[:value]

app/models/alchemy/ingredients/picture.rb

@@ -38,6 +38,10 @@ class Picture < Alchemy::Ingredient
         upsample
       ]
 
+      def preload_relations
+        [:thumbs]
+      end
+
       # The first 30 characters of the pictures name
       #
       # Used by the Element#preview_text method.

spec/models/alchemy/ingredient_spec.rb

@@ -213,4 +213,12 @@
       )
     end
   end
+
+  describe "#preload_relations" do
+    let(:ingredient) { Alchemy::Ingredients::Text.new(role: "intro", element: element) }
+
+    subject { ingredient.preload_relations }
+
+    it { is_expected.to eq([]) }
+  end
 end

spec/models/alchemy/ingredients/picture_spec.rb

@@ -125,4 +125,12 @@
       )
     end
   end
+
+  describe "#preload_relations" do
+    let(:ingredient) { described_class.new }
+
+    subject { ingredient.preload_relations }
+
+    it { is_expected.to eq([:thumbs]) }
+  end
 end