diff --git a/gruntfile.js b/gruntfile.js
index 480b9b0cd..9114273cb 100644
--- a/gruntfile.js
+++ b/gruntfile.js
@@ -121,6 +121,7 @@ module.exports = function ( grunt ) {
 					'!vendor/**/*',
 					'!package/**/*',
 					'!php/media/class-filter.php',
+					'!php/misc/class-image-sizes-no-textdomain.php',
 				],
 			},
 		},
diff --git a/php/class-utils.php b/php/class-utils.php
index 4c6569e29..f88c307e8 100644
--- a/php/class-utils.php
+++ b/php/class-utils.php
@@ -7,6 +7,7 @@
 
 namespace Cloudinary;
 
+use Cloudinary\Misc\Image_Sizes_No_Textdomain;
 use Cloudinary\Settings\Setting;
 use Google\Web_Stories\Story_Post_Type;
 use WP_Post;
@@ -472,7 +473,7 @@ public static function get_support_link( $args = array() ) {
 					$plugin->version
 				)
 			),
-			'tf_description'  => esc_attr( __( 'Please, provide more details on your request, and if possible, attach a System Report', 'cloudinary' ) ),
+			'tf_description'               => esc_attr( __( 'Please, provide more details on your request, and if possible, attach a System Report', 'cloudinary' ) ),
 		);
 
 		$args = wp_parse_args(
@@ -924,15 +925,7 @@ public static function get_registered_sizes( $attachment_id = null ) {
 		/** This filter is documented in wp-admin/includes/media.php */
 		$image_sizes = apply_filters(
 			'image_size_names_choose',
-			array(
-				// phpcs:disable WordPress.WP.I18n.MissingArgDomain
-				'thumbnail'    => __( 'Thumbnail' ),
-				'medium'       => __( 'Medium' ),
-				'medium_large' => __( 'Medium Large' ),
-				'large'        => __( 'Large' ),
-				'full'         => __( 'Full Size' ),
-				// phpcs:enable WordPress.WP.I18n.MissingArgDomain
-			)
+			Image_Sizes_No_Textdomain::get_image_sizes()
 		);
 
 		$labels = wp_parse_args( $labels, $image_sizes );
diff --git a/php/misc/class-image-sizes-no-textdomain.php b/php/misc/class-image-sizes-no-textdomain.php
new file mode 100644
index 000000000..9f28eee0b
--- /dev/null
+++ b/php/misc/class-image-sizes-no-textdomain.php
@@ -0,0 +1,36 @@
+<?php
+/**
+ * Returns image sizes used in `class-utils.php`.
+ *
+ * These sizes are defined in a separate file, because the `addtextdomain`
+ * task in `gruntfile.js` would otherwise try to add our textdomain to
+ * them, which we don't want.
+ *
+ * We need these size names to use the default WordPress translations.
+ *
+ * @package Cloudinary
+ */
+
+namespace Cloudinary\Misc;
+
+/**
+ * Class Image_Sizes_No_Textdomain
+ */
+class Image_Sizes_No_Textdomain {
+	/**
+	 * Get image sizes.
+	 *
+	 * @return array
+	 */
+	public static function get_image_sizes() {
+		return array(
+			// phpcs:disable WordPress.WP.I18n.MissingArgDomain
+			'thumbnail'    => __( 'Thumbnail' ),
+			'medium'       => __( 'Medium' ),
+			'medium_large' => __( 'Medium Large' ),
+			'large'        => __( 'Large' ),
+			'full'         => __( 'Full Size' ),
+			// phpcs:enable WordPress.WP.I18n.MissingArgDomain
+		);
+	}
+}