diff --git a/safe-svg.php b/safe-svg.php
index 2b6b1bc3..3dd2dbdf 100644
--- a/safe-svg.php
+++ b/safe-svg.php
@@ -698,7 +698,7 @@ protected function svg_dimensions( $attachment_id ) {
 		 * @param int    $attachment_id The image attachment ID.
 		 */
 		public function disable_srcset( $image_meta, $size_array, $image_src, $attachment_id ) {
-			if ( $attachment_id && 'image/svg+xml' === get_post_mime_type( $attachment_id ) ) {
+			if ( $attachment_id && 'image/svg+xml' === get_post_mime_type( $attachment_id ) && is_array( $image_meta ) ) {
 				$image_meta['sizes'] = array();
 			}