Spiderable/PhantomJS and jQuery Fotorama image slider

We are using Fotorama plugin to display product images.
Example here https://fastfred.de/steba-kb27-mini-backofen/p28742026

But if the same page is requested by search engines (using Spiderable and PhantomJS), Fotorama is always shown as “loading”. Images are never displayed.
Check it here https://fastfred.de/steba-kb27-mini-backofen/p28742026?escaped_fragment=

How is it possible to make images inside Fotorama plugin “visible” to search engines?