Using align(both) collapses div?

[blaasvaer]

When I have this markup:

<span class="jewellery_image" data-id="<?php the_ID(); ?>">
    <a class="image_link" href=""><?php the_post_thumbnail('medium'); ?></a>
    <a class="title" href=""><?php the_title(); ?></a>
</span>

And this (s)css:

.jewellery_image {
    @include column(1/4, $cycle: 4, $gutter: 1);

    img {
        @include align(both);
    }
}

The box (.jewellery_image) collapses. And I have to specify a height (in px as % doesn't work) for it to not have it collapse.

Is this by design or a bug?

I've tried all possible display modes for all parent and child elements to make it work, but only specifying a height for .jewellery_image will work.