content-child.php { Pinboard, setting up default thumbnail }

<article <?php post_class(); ?> id="post-<?php the_ID(); ?>">
    <div class="entry">
        <?php if( ! pinboard_post_is_full_width() ) { ?>
        <?php if ( has_post_thumbnail() ) { ?>
                    <?php pinboard_post_thumbnail(); ?>
        <?php } else { ?>
                    <figure class="entry-thumbnail">
                        <a href="<?php the_permalink(); ?>" rel="bookmark" title="<?php the_title_attribute(); ?>">
                            <img width="auto" height="auto" src="http://bhsolutions.eu/wp-content/uploads/2013/09/BH_h250.png" class="attachment-teaser-thumb wp-post-image" alt="<?php the_title_attribute(); ?>"></img>
                        </a>
                    </figure>
        <?php }
        }
        ?>
        <div class="entry-container">
            <header class="entry-header">
                <<?php pinboard_title_tag( 'post' ); ?> class="entry-title">
                    <?php the_title(); ?>
                </<?php pinboard_title_tag( 'post' ); ?>>

                <?php if( pinboard_post_is_full_width() ) : ?>
                    <?php pinboard_entry_meta(); ?>
                <?php endif; ?>
            </header><!-- .entry-header -->
            <?php if( pinboard_post_is_full_width() ) : ?>
                <?php pinboard_post_thumbnail(); ?>
            <?php endif; ?>
            <?php if( ! is_category( pinboard_get_option( 'portfolio_cat' ) ) && ! ( is_category() && cat_is_ancestor_of( pinboard_get_option( 'portfolio_cat' ), get_queried_object() ) ) ) : ?>
                <div class="entry-summary">
                    <?php // the_excerpt(); ?>
                </div><!-- .entry-summary -->
            <?php endif; ?>
            <div class="clear"></div>
        </div><!-- .entry-container -->
        <?php if( ! pinboard_post_is_full_width() ) : ?>
            <?php pinboard_entry_meta(); ?>
        <?php endif; ?>
    </div><!-- .entry -->
</article><!-- .post -->