Changed regex so it could only start with width or height.

library/responsive-images.php

@@ -61,7 +61,7 @@ function foundationpress_adjust_image_sizes_attr( $sizes, $size ) {
 // Remove inline width and height attributes for post thumbnails
 function remove_thumbnail_dimensions( $html, $post_id, $post_image_id ) {
     if(!strpos($html, 'attachment-shop_single')) {
-        $html = preg_replace( '/(width|height)=\"\d*\"\s/', '', $html );
+        $html = preg_replace( '/^(width|height)=\"\d*\"\s/', '', $html );
     }
     return $html;
 }