Yes. Sorry I mixed myself. Sometimes ideas are not that clear on the evening :( Sure you don't need to translate the pictures.
To try to clarify:
With some themes, you have to do like this: include all images in all languages in theme options and Polylang just filters them by language on front page. It depends much on how the theme has been written to make this work.
Have you custom post types listed in Polylang settings?