diff --git a/src/wp-admin/includes/image-edit.php b/src/wp-admin/includes/image-edit.php
index 7f9ebf7f9f875..0c20e4a605b4f 100644
--- a/src/wp-admin/includes/image-edit.php
+++ b/src/wp-admin/includes/image-edit.php
@@ -787,7 +787,12 @@ function stream_preview_image( $post_id ) {
 		return false;
 	}
 
-	return wp_stream_image( $img, $post->post_mime_type, $post_id );
+	$mime_type = $post->post_mime_type;
+	if ( method_exists( $img, 'get_mime_type' ) ) {
+		$mime_type = $img->get_mime_type();
+	}
+
+	return wp_stream_image( $img, $mime_type, $post_id );
 }
 
 /**