diff --git a/.github/actions/update-package/build-lazy-images.sh b/.github/actions/update-package/build-lazy-images.sh
new file mode 100755
index 0000000000000..6c9231beb1452
--- /dev/null
+++ b/.github/actions/update-package/build-lazy-images.sh
@@ -0,0 +1,10 @@
+#!/bin/bash
+
+set -eo pipefail
+
+# We want ./dist in the mirror, so remove it from .gitignore.
+sed -i '/^dist$/d' .gitignore
+
+# Build JS.
+yarn
+yarn build
diff --git a/.github/actions/update-package/update-package.sh b/.github/actions/update-package/update-package.sh
index 7359a7271c1d0..6542d750c4907 100644
--- a/.github/actions/update-package/update-package.sh
+++ b/.github/actions/update-package/update-package.sh
@@ -66,6 +66,11 @@ for package in packages/*; do
 
 	cp -r $BASE/packages/$NAME/. .
 
+	# Run package build script, if any.
+	if [[ -e $BASE/.github/actions/update-package/build-$NAME.sh ]]; then
+		$BASE/.github/actions/update-package/build-$NAME.sh
+	fi
+
 	# Before we commit any changes, ensure that the repo has the basics we need for any package.
 	if $COMPOSER_JSON_EXISTED && [ ! -f "composer.json" ]; then
 		echo "  Those changes remove essential parts of the package. They will not be committed."
diff --git a/.github/workflows/update-package.yml b/.github/workflows/update-package.yml
index 89561f23249d4..9ce3234ddefd3 100644
--- a/.github/workflows/update-package.yml
+++ b/.github/workflows/update-package.yml
@@ -12,6 +12,11 @@ jobs:
     if: github.event.pull_request.head.repo.full_name == github.event.pull_request.base.repo.full_name
     steps:
       - uses: actions/checkout@master
+
+      - name: Tool versions
+        run: |
+          yarn --version
+
       - name: Keep Jetpack Packages up to date
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}