diff --git a/includes/wc-template-functions.php b/includes/wc-template-functions.php
index 51e05245fec..a3444283033 100644
--- a/includes/wc-template-functions.php
+++ b/includes/wc-template-functions.php
@@ -1053,6 +1053,8 @@ if ( ! function_exists( 'woocommerce_show_product_thumbnails' ) ) {
 /**
  * Get HTML for a gallery image.
  *
+ * woocommerce_gallery_thumbnail_size, woocommerce_gallery_image_size and woocommerce_gallery_full_size accept name based image sizes, or an array of width/height values.
+ *
  * @since 3.3.2
  * @param int $attachment_id
  * @param bool $main_image Is this the main image or a thumbnail?
diff --git a/templates/single-product/product-image.php b/templates/single-product/product-image.php
index ab3217b345e..f410108fc8b 100644
--- a/templates/single-product/product-image.php
+++ b/templates/single-product/product-image.php
@@ -18,6 +18,11 @@
 
 defined( 'ABSPATH' ) || exit;
 
+// Note: `wc_get_gallery_image_html` was added in WC 3.3.2 and did not exist prior. This check protects against theme overrides being used on older versions of WC.
+if ( ! function_exists( 'wc_get_gallery_image_html' ) ) {
+	return;
+}
+
 global $product;
 
 $columns           = apply_filters( 'woocommerce_product_thumbnails_columns', 4 );
@@ -33,7 +38,6 @@ $wrapper_classes   = apply_filters( 'woocommerce_single_product_image_gallery_cl
 	<figure class="woocommerce-product-gallery__wrapper">
 		<?php
 		if ( has_post_thumbnail() ) {
-			// Note: `wc_get_gallery_image_html` was added in WC 3.3.2 and did not exist prior.
 			$html  = wc_get_gallery_image_html( $post_thumbnail_id, true );
 		} else {
 			$html  = '<div class="woocommerce-product-gallery__image--placeholder">';
diff --git a/templates/single-product/product-thumbnails.php b/templates/single-product/product-thumbnails.php
index b9d14bc0a23..b3e06a4ceb3 100644
--- a/templates/single-product/product-thumbnails.php
+++ b/templates/single-product/product-thumbnails.php
@@ -18,13 +18,17 @@
 
 defined( 'ABSPATH' ) || exit;
 
+// Note: `wc_get_gallery_image_html` was added in WC 3.3.2 and did not exist prior. This check protects against theme overrides being used on older versions of WC.
+if ( ! function_exists( 'wc_get_gallery_image_html' ) ) {
+	return;
+}
+
 global $product;
 
 $attachment_ids = $product->get_gallery_image_ids();
 
 if ( $attachment_ids && has_post_thumbnail() ) {
 	foreach ( $attachment_ids as $attachment_id ) {
-		// Note: `wc_get_gallery_image_html` was added in WC 3.3.2 and did not exist prior.
 		echo apply_filters( 'woocommerce_single_product_image_thumbnail_html', wc_get_gallery_image_html( $attachment_id  ), $attachment_id );
 	}
 }