No WP Thumbnail Images

Comment on SEO Recent Posts WordPress Widget by Andrei.

Something unhappy happened with my settings:
>>Have you turned the thumbnail images feature on under “Stallion Theme” >> “Colour >>Options” : “Thumbnails” – “Auto and Featured Thumbnails ON**” or “Featured Thumbnails >>Only ON”

I set “Auto and Featured Thumbnails ON**”

>>On an unrelated note: Looks like you might have to set your /cache/ folder >>permissions so the thumbnails on your Popular Posts widget etc… work.
>>You’ll need to log into your site using an FTP program like Filezilla and go to
>>/wp-content/themes/stallion-responsive-child/cache/

Set to 777 (before was 755).

Then I regenerated thumbnails.
No thumbnails are shown on my site however :(.
BTW, wp-content/themes/stallion-responsive-child/cache is empty

I have certainly missed something, but what?