Hi Anna,
Similar to previous issues like this, they just need templates added to the category listings. You can see an issue is filed here:
But no one has contributed a fix for this yet. To do it, you just need to copy over the default catalogCategory.tpl template to the bootstrap3 theme, and then update it to use the same media list used elsewhere in the theme (for example, in search results).
A pull request for Bootstrap3 would be very welcome!