diff --git a/features/media-regenerate.feature b/features/media-regenerate.feature
index fb4f99be60..0981e41c87 100644
--- a/features/media-regenerate.feature
+++ b/features/media-regenerate.feature
@@ -144,3 +144,51 @@ Feature: Regenerate WordPress attachments
       """
       Success: Finished regenerating all images.
       """
+
+  Scenario: Regenerate images which are missing globally-defined image sizes
+    Given download:
+      | path                        | url                                              |
+      | {CACHE_DIR}/large-image.jpg | http://wp-cli.org/behat-data/large-image.jpg     |
+    And I run `wp option update uploads_use_yearmonth_folders 0`
+
+    When I run `wp media import {CACHE_DIR}/large-image.jpg --title="My imported attachment" --porcelain`
+    Then save STDOUT as {ATTACHMENT_ID}
+    And the wp-content/uploads/large-image-100x100.jpg file should not exist
+
+    Given a wp-content/mu-plugins/media-settings.php file:
+      """
+      <?php
+      add_action( 'after_setup_theme', function(){
+        add_image_size( 'test1', 100, 100, true );
+      });
+      """
+
+    When I run `wp media regenerate --only-missing --yes`
+    Then STDOUT should contain:
+      """
+      Found 1 image to regenerate.
+      """
+    And STDOUT should contain:
+      """
+      Regenerated thumbnails for "My imported attachment"
+      """
+    And STDOUT should contain:
+      """
+      Success: Finished regenerating the image.
+      """
+    And the wp-content/uploads/large-image-100x100.jpg file should exist
+
+    When I run `wp media regenerate --only-missing --yes`
+    Then STDOUT should contain:
+      """
+      Found 1 image to regenerate
+      """
+    And STDOUT should contain:
+      """
+      No thumbnail regeneration needed for "My imported attachment"
+      """
+    And STDOUT should contain:
+      """
+      Success: Finished regenerating the image.
+      """
+    And the wp-content/uploads/large-image-100x100.jpg file should exist
diff --git a/php/commands/media.php b/php/commands/media.php
index fd77715e4c..df37e75215 100644
--- a/php/commands/media.php
+++ b/php/commands/media.php
@@ -315,7 +315,11 @@ private function needs_regeneration( $att_id ) {
 		$original_path = $dir_path . basename( $metadata['file'] );
 
 		if ( empty( $metadata['sizes'] ) ) {
-			return false;
+			return true;
+		}
+
+		if ( array_diff( get_intermediate_image_sizes(), array_keys( $metadata['sizes'] ) ) ) {
+			return true;
 		}
 
 		foreach( $metadata['sizes'] as $size_info ) {