diff --git a/app/jobs/processing/abstract_unstick_attachments_job.rb b/app/jobs/processing/abstract_unstick_attachments_job.rb
new file mode 100644
index 00000000..ce781a3f
--- /dev/null
+++ b/app/jobs/processing/abstract_unstick_attachments_job.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module Processing
+  # @abstract
+  class AbstractUnstickAttachmentsJob < ApplicationJob
+    extend Dry::Core::ClassAttributes
+
+    include JobIteration::Iteration
+
+    defines :model_klass, type: Support::Types::ModelClass
+
+    model_klass ApplicationRecord
+
+    queue_as :maintenance
+
+    # @param [String] cursor
+    # @return [void]
+    def build_enumerator(cursor:)
+      enumerator_builder.active_record_on_records(
+        model_klass.with_any_stuck_shrine_attachments,
+        cursor:
+      )
+    end
+
+    # @param [ApplicationRecord] model
+    # @return [void]
+    def each_iteration(model)
+      model.unstick_shrine_attachments!
+    end
+
+    private
+
+    def model_klass = self.class.model_klass
+  end
+end
diff --git a/app/jobs/processing/unstick_collection_attachments_job.rb b/app/jobs/processing/unstick_collection_attachments_job.rb
new file mode 100644
index 00000000..270c2d69
--- /dev/null
+++ b/app/jobs/processing/unstick_collection_attachments_job.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module Processing
+  # @see Collection
+  class UnstickCollectionAttachmentsJob < AbstractUnstickAttachmentsJob
+    model_klass Collection
+  end
+end
diff --git a/app/jobs/processing/unstick_community_attachments_job.rb b/app/jobs/processing/unstick_community_attachments_job.rb
new file mode 100644
index 00000000..a4970986
--- /dev/null
+++ b/app/jobs/processing/unstick_community_attachments_job.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module Processing
+  # @see Community
+  class UnstickCommunityAttachmentsJob < AbstractUnstickAttachmentsJob
+    model_klass Community
+  end
+end
diff --git a/app/jobs/processing/unstick_item_attachments_job.rb b/app/jobs/processing/unstick_item_attachments_job.rb
new file mode 100644
index 00000000..cb0f6b34
--- /dev/null
+++ b/app/jobs/processing/unstick_item_attachments_job.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module Processing
+  # @see Item
+  class UnstickItemAttachmentsJob < AbstractUnstickAttachmentsJob
+    model_klass Item
+  end
+end
diff --git a/app/services/processing/model_integration.rb b/app/services/processing/model_integration.rb
index eb42f3a3..1ccc4f77 100644
--- a/app/services/processing/model_integration.rb
+++ b/app/services/processing/model_integration.rb
@@ -8,6 +8,8 @@ module ModelIntegration
 
     include Support::ClassyList::DSL
 
+    STALE_TIME = 15.minutes
+
     included do
       has_simple_symbol_list! :shrine_attachments
     end
@@ -57,10 +59,28 @@ def shrine_attacher_for(name) = __send__("#{name}_attacher")
     # @return [<Symbol>]
     def shrine_attachment_names = self.class.shrine_attachment_names
 
+    # @return [{ Symbol => Shrine::Attacher }]
+    def shrine_attachers = shrine_attachment_names.index_with { |name| shrine_attacher_for(name) }
+
     # @raise [Shrine::Error] if there is no file data
     # @return [Hash]
     def shrine_file_data_for(name) = shrine_attacher_for(name).file_data
 
+    # @!group Stuck Attachment Handling
+
+    # @return [{ Symbol => Boolean }]
+    def unstick_shrine_attachments!
+      shrine_attachers.each_with_object({}) do |(name, attacher), result|
+        stuck = attacher.stuck?
+
+        retry_promoting_attachment!(name) if stuck
+
+        result[name] = stuck
+      end
+    end
+
+    # @!endgroup Stuck Attachment Handling
+
     module ClassMethods
       # @param [Symbol] name
       # @return [void]
@@ -156,6 +176,49 @@ def arel_shrine_with_derivatives_condition(attr, with_derivatives)
           # simplecov:enable
         end
       end
+
+      # @!group Stuck Attachment Handling
+
+      def with_any_stuck_shrine_attachments = with_stuck_shrine_attachments(shrine_attachment_names)
+
+      def with_stuck_shrine_attachments(*names)
+        names.flatten!
+
+        return none if names.empty?
+
+        conditions = names.map do |name|
+          arel_attachment_stuck(name)
+        end
+
+        expr = arel_grouping(arel_or_expressions(conditions))
+
+        where(expr)
+      end
+
+      def arel_attachment_stuck(name, column: "#{name}_data")
+        cached = arel_shrine_storage_condition(arel_table[column], "cache")
+        stale = arel_attachment_stale(name, column:)
+
+        arel_grouped cached.and(stale)
+      end
+
+      def arel_attachment_generated_at(name, column: "#{name}_data")
+        attr = arel_table[column]
+
+        arel_cast(arel_json_get_path_as_text(attr, "metadata", "generated_at"), "timestamptz")
+      end
+
+      def arel_attachment_stale(name, column: "#{name}_data")
+        generated_at = arel_attachment_generated_at(name, column:)
+
+        is_stale = generated_at.lt(STALE_TIME.ago)
+
+        unset = generated_at.eq(nil)
+
+        arel_grouped is_stale.or(unset)
+      end
+
+      # @!endgroup Stuck Attachment Handling
     end
   end
 end
diff --git a/app/services/processing/types.rb b/app/services/processing/types.rb
index ee292361..b7794e7d 100644
--- a/app/services/processing/types.rb
+++ b/app/services/processing/types.rb
@@ -19,7 +19,12 @@ module Types
 
     AttachmentName = Coercible::Symbol
 
-    AttachmentData = Hash | String
+    FileData = Hash.schema(
+      id?: Coercible::String,
+      storage?: Coercible::String,
+    ).with_key_transform(&:to_sym)
+
+    AttachmentData = FileData | String
 
     Model = ::Support::Models::Types::Model
   end
diff --git a/app/uploaders/cached_asset_uploader.rb b/app/uploaders/cached_asset_uploader.rb
index 7e109757..5d0631db 100644
--- a/app/uploaders/cached_asset_uploader.rb
+++ b/app/uploaders/cached_asset_uploader.rb
@@ -8,23 +8,12 @@
 #
 # @see HarvestCachedAsset
 class CachedAssetUploader < Shrine
-  plugin :add_metadata
-  plugin :refresh_metadata
   plugin :infer_extension, force: true
   plugin :remote_url, max_size: 5.gigabytes, downloader: ::Support::Networking::SHRINE_REMOTE_URL_DOWNLOADER
-  plugin :signature
   plugin :validation_helpers
   plugin :restore_cached_data
   plugin :metadata_attributes, filename: "file_name", size: "file_size", mime_type: "content_type", sha256: "signature"
 
-  add_metadata :generated_at do |io, **|
-    Time.current.iso8601
-  end
-
-  add_metadata :sha256, skip_nil: true do |io, store: nil, **options|
-    calculate_signature(io, :sha256, format: :base64) unless store == :cache
-  end
-
   add_metadata skip_nil: true do |io, metadata:, **|
     # Deal with invalid unicode encoding in filenames
 
diff --git a/app/uploaders/generic_uploader.rb b/app/uploaders/generic_uploader.rb
index 04afcb13..21ad7481 100644
--- a/app/uploaders/generic_uploader.rb
+++ b/app/uploaders/generic_uploader.rb
@@ -5,23 +5,12 @@
 #
 # It stores some metadata about the kind of asset it detects, see {Assets::ParseKind}.
 class GenericUploader < Shrine
-  plugin :add_metadata
-  plugin :refresh_metadata
   plugin :infer_extension, force: true
   plugin :remote_url, max_size: 3.gigabytes, downloader: ::Support::Networking::SHRINE_REMOTE_URL_DOWNLOADER
-  plugin :signature
   plugin :validation_helpers
   plugin :restore_cached_data
   plugin :metadata_attributes, kind: "kind", filename: "file_name", size: "file_size", mime_type: "content_type"
 
-  add_metadata :generated_at do |io, **|
-    Time.current.iso8601
-  end
-
-  add_metadata :sha256, skip_nil: true do |io, store: nil, **options|
-    calculate_signature(io, :sha256, format: :base64) unless store == :cache
-  end
-
   add_metadata :kind do |io, **options|
     MeruAPI::Container["assets.parse_kind"].call(io).value_or("unknown")
   end
diff --git a/app/uploaders/image_uploader.rb b/app/uploaders/image_uploader.rb
index cd929cfe..17a12a38 100644
--- a/app/uploaders/image_uploader.rb
+++ b/app/uploaders/image_uploader.rb
@@ -4,11 +4,8 @@
 #
 # @see ImageAttachments::ImageWrapper
 class ImageUploader < Shrine
-  plugin :add_metadata
-  plugin :refresh_metadata
   plugin :remote_url, max_size: 100.megabytes, downloader: ::Support::Networking::SHRINE_REMOTE_URL_DOWNLOADER
   plugin :store_dimensions, analyzer: :ruby_vips
-  plugin :signature
   plugin :validation_helpers
   plugin :restore_cached_data
 
@@ -18,14 +15,6 @@ class ImageUploader < Shrine
 
   metadata_method :alt
 
-  add_metadata :generated_at do |io, **|
-    Time.current.iso8601
-  end
-
-  add_metadata :sha256 do |io, derivative: nil, **|
-    calculate_signature(io, :sha256, format: :base64) unless derivative
-  end
-
   Attacher.validate do
     validate_mime_type %w[image/jpg image/jpeg image/png image/tiff image/webp image/heic image/heif image/gif image/svg+xml]
   end
diff --git a/app/uploaders/site_logo_uploader.rb b/app/uploaders/site_logo_uploader.rb
index ee8ff15a..bf6a0aca 100644
--- a/app/uploaders/site_logo_uploader.rb
+++ b/app/uploaders/site_logo_uploader.rb
@@ -4,11 +4,8 @@
 #
 # @see ImageAttachments::SiteLogoWrapper
 class SiteLogoUploader < Shrine
-  plugin :add_metadata
-  plugin :refresh_metadata
   plugin :remote_url, max_size: 100.megabytes, downloader: ::Support::Networking::SHRINE_REMOTE_URL_DOWNLOADER
   plugin :store_dimensions, analyzer: :ruby_vips
-  plugin :signature
   plugin :validation_helpers
   plugin :restore_cached_data
 
@@ -18,14 +15,6 @@ class SiteLogoUploader < Shrine
 
   metadata_method :alt
 
-  add_metadata :generated_at do |io, **|
-    Time.current.iso8601
-  end
-
-  add_metadata :sha256 do |io, derivative: nil, **|
-    calculate_signature(io, :sha256, format: :base64) unless derivative
-  end
-
   Attacher.validate do
     validate_mime_type %w[image/jpg image/jpeg image/png image/tiff image/webp image/heic image/heif image/gif image/svg+xml]
   end
diff --git a/config/initializers/900_good_job.rb b/config/initializers/900_good_job.rb
index 8cd629b0..5f172f64 100644
--- a/config/initializers/900_good_job.rb
+++ b/config/initializers/900_good_job.rb
@@ -116,6 +116,21 @@
       description: "Process stale orderings",
       args: -> { [Time.current.iso8601] },
     },
+    "processing.unstick_collection_attachments": {
+      cron: "0,20,40 * * * *",
+      class: "Processing::UnstickCollectionAttachmentsJob",
+      description: "Unstick collection attachments",
+    },
+    "processing.unstick_community_attachments": {
+      cron: "0,20,40 * * * *",
+      class: "Processing::UnstickCommunityAttachmentsJob",
+      description: "Unstick community attachments",
+    },
+    "processing.unstick_item_attachments": {
+      cron: "0,20,40 * * * *",
+      class: "Processing::UnstickItemAttachmentsJob",
+      description: "Unstick item attachments",
+    },
     "rendering.process_stale_entities": {
       cron: "*/5 * * * *",
       class: "Rendering::ProcessStaleEntitiesJob",
diff --git a/lib/support/boot/501_shrine_standard_metadata.rb b/lib/support/boot/501_shrine_standard_metadata.rb
new file mode 100644
index 00000000..fe2fa49b
--- /dev/null
+++ b/lib/support/boot/501_shrine_standard_metadata.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+class Shrine
+  module Plugins
+    module StandardMetadata
+      STALE_TIME = 15.minutes
+
+      SafeTime = Dry::Types["params.time"].optional.fallback(nil)
+
+      class << self
+        def configure(uploader, **options)
+          uploader.opts[:standard_metadata] ||= {}
+          uploader.opts[:standard_metadata].merge!(options)
+          uploader.opts[:standard_metadata][:stale_time] ||= STALE_TIME
+
+          uploader.add_metadata :generated_at, skip_nil: true do |io, store: nil, **|
+            Time.current.iso8601 unless store.nil?
+          end
+
+          uploader.add_metadata :sha256, skip_nil: true do |io, store: nil, **options|
+            calculate_signature(io, :sha256, format: :base64) unless store.nil?
+          end
+        end
+
+        # @return [void]
+        def load_dependencies(uploader, **options)
+          uploader.plugin :self_registering
+          uploader.plugin :signature
+          uploader.plugin :add_metadata
+          uploader.plugin :refresh_metadata
+        end
+      end
+
+      module InstanceMethods
+        def stale_at = stale_time.ago
+
+        def stale_time = opts.dig(:standard_metadata, :stale_time) || STALE_TIME
+      end
+
+      module AttacherMethods
+        def stale? = file.stale?
+
+        def stuck? = cached? && stale?
+      end
+
+      module FileMethods
+        def generated_at = metadata["generated_at"].then { Shrine::Plugins::StandardMetadata::SafeTime.(_1) if _1.present? }
+
+        def stale_at = uploader.stale_at
+
+        def stale? = generated_at.then { _1.nil? || _1 < stale_at }
+      end
+    end
+
+    register_plugin(:standard_metadata, StandardMetadata)
+  end
+end
+
+# Enable the plugin automatically
+Shrine.plugin :standard_metadata
diff --git a/spec/models/collection_spec.rb b/spec/models/collection_spec.rb
index 7b5b1cd1..531fcf1e 100644
--- a/spec/models/collection_spec.rb
+++ b/spec/models/collection_spec.rb
@@ -72,4 +72,15 @@
       end
     end
   end
+
+  context "when attaching a thumbnail image" do
+    let(:thumbnail_path) { Rails.root.join("spec", "data", "lorempixel.jpg") }
+
+    it "attaches the thumbnail for processing" do
+      expect do
+        collection.thumbnail = thumbnail_path.open("rb+")
+        collection.save!
+      end.to have_enqueued_job(Processing::PromoteAttachmentJob)
+    end
+  end
 end
diff --git a/spec/requests/graphql/mutations/update_collection_spec.rb b/spec/requests/graphql/mutations/update_collection_spec.rb
index c11a373d..53ec0695 100644
--- a/spec/requests/graphql/mutations/update_collection_spec.rb
+++ b/spec/requests/graphql/mutations/update_collection_spec.rb
@@ -182,6 +182,29 @@
       end
     end
 
+    context "when updating a thumbnail" do
+      include_context "with stubbed revalidation"
+
+      let(:clear_thumbnail) { false }
+
+      let(:new_thumbnail) do
+        graphql_upload_from "spec", "data", "lorempixel.jpg"
+      end
+
+      it "updates the thumbnail" do
+        expect_request! do |req|
+          req.effect! change { collection.reload.thumbnail.id }.to(be_present)
+          req.effect! have_enqueued_job(Processing::PromoteAttachmentJob).once
+
+          req.data! expected_shape
+        end
+
+        expect do
+          perform_enqueued_jobs
+        end.to change { collection.reload.thumbnail_data["storage"] }.from("cache").to("store")
+      end
+    end
+
     context "when clearing a thumbnail" do
       let!(:clear_thumbnail) { true }
 
diff --git a/spec/support/contexts/stubbed_revalidation.rb b/spec/support/contexts/stubbed_revalidation.rb
new file mode 100644
index 00000000..63b5b6af
--- /dev/null
+++ b/spec/support/contexts/stubbed_revalidation.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+RSpec.shared_context "with stubbed entity revalidation" do
+  before do
+    endpoint = Frontend::Cache::EntityRevalidator.endpoint
+
+    now = Time.current.to_i * 1000
+
+    body = { revalidated: true, now:, }.to_json
+
+    headers = { "Content-Type" => "application/json" }
+
+    stub_request(:delete, endpoint)
+      .to_return(status: 200, body:, headers:)
+  end
+end
+
+RSpec.shared_context "with stubbed instance revalidation" do
+  include_context "with stubbed entity revalidation"
+
+  before do
+    endpoint = Frontend::Cache::InstanceRevalidator.endpoint
+
+    now = Time.current.to_i * 1000
+
+    body = { revalidated: true, now:, }.to_json
+
+    headers = { "Content-Type" => "application/json" }
+
+    stub_request(:delete, endpoint)
+      .to_return(status: 200, body:, headers:)
+  end
+end
+
+RSpec.shared_context "with stubbed revalidation" do
+  include_context "with stubbed entity revalidation"
+  include_context "with stubbed instance revalidation"
+end