[Theme Horse Support Team]

Hi jonas,
Yes the featured image will not be displayed on Page. Featured image are designed to display only on home page or on blog page. We have designed our theme this way. It was from the beginning from version 1.0. You told that after your last update your featured image is lost. That means you have customized a code on the theme. If you make direct code customization on the theme then while updating to new version all your customized code will be lost. So we recommended you not to change any code on the parent theme. Customize any thing on the child theme.

GO to theme folder -> inc -> structure -> content-extension.php on line no 215 you will find this code <article> Add below code just below <article> tag

if( has_post_thumbnail() ) {
$image = '';        			
$title_attribute = the_title_attribute( array( 'echo' => false ) );
$image .= '<figure class="post-featured-image">';
$image .= '<a href="' . get_permalink() . '" title="'.the_title( '', '', false ).'">';
$image .= get_the_post_thumbnail( $post->ID, 'featured', array( 'title' => esc_attr( $title_attribute ), 'alt' => esc_attr( $title_attribute ) ) ).'</a>';
$image .='<span class="arrow"></span>';
$image .= '</figure>';
echo $image;
}

Remember create a child theme and then customize the code. Otherwise if there is a change on the code then the above code must be added each and every time when you update to latest version.

Add below code on your functions.php

<?php

// Unhook default Thematic functions
function unhook_thematic_functions() {
    // Don't forget the position number if the original function has one

remove_action( 'interface_loop_content', 'interface_theloop', 10 );

}
add_action('init','unhook_thematic_functions'); // removes the header content by using hook interface_header

add_action( 'interface_loop_content', 'interface_child_loop_content' );

function interface_child_loop_content() {
	if( is_page() ) {
		if( is_page_template( 'page-templates/page-template-blog-image-large.php' ) ) {
			
			interface_theloop_for_template_blog_image_large();
			
		}
		elseif( is_page_template( 'page-templates/page-template-blog-image-medium.php' ) ) {
			interface_theloop_for_template_blog_image_medium();
		}
		elseif( is_page_template( 'page-templates/page-template-blog-full-content.php' ) ) {
			
			interface_theloop_for_template_blog_full_content();
			
		}
		else {
			interface_child_theloop_for_page();
		}
	}
	elseif( is_single() ) {
		interface_child_theloop_for_single();
	}
	elseif( is_search() ) {
		interface_child_theloop_for_search();
	}
	else {
		interface_child_theloop_for_archive();
	}
} 

/****************************************************************************************/
/****************************************************************************************/

if ( ! function_exists( 'interface_child_theloop_for_archive' ) ) :
/**
 * Fuction to show the archive loop content.
 */
function interface_child_theloop_for_archive() {
	global $post;

	if( have_posts() ) {
		while( have_posts() ) {
			the_post();

			do_action( 'interface_before_post' );
?>

<section id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
  <?php do_action( 'interface_before_post_header' ); ?>
  <article>
    <?php
				if( has_post_thumbnail() ) {
					$image = '';        			
		     		$title_attribute = the_title_attribute( array( 'echo' => false ) );
		     		$image .= '<figure class="post-featured-image">';
		  			$image .= '<a href="' . get_permalink() . '" title="'.the_title( '', '', false ).'">';
		  			$image .= get_the_post_thumbnail( $post->ID, 'featured', array( 'title' => esc_attr( $title_attribute ), 'alt' => esc_attr( $title_attribute ) ) ).'</a>';
					$image .='<span class="arrow"></span>';
		  			$image .= '</figure>';

		  			echo $image;
		  		}
	  			?>
    <header class="entry-header">
      <?php if (get_the_author() !=''){?>
      <div class="entry-meta"> <span class="cat-links">
        <?php the_category(', '); ?>
        </span><!-- .cat-links --> 
      </div>
      <?php } ?>
      <!-- .entry-meta -->
      <h2 class="entry-title"> <a href="<?php the_permalink(); ?>" title="<?php the_title_attribute();?>">
        <?php the_title();?>
        </a> </h2>
      <!-- .entry-title -->
       <?php if (has_category() !=''){?>
      <div class="entry-meta clearfix">
        <div class="by-author vcard author"><span class="fn"><a href="<?php echo get_author_posts_url( get_the_author_meta( 'ID' ) ); ?>" 
                        title="<?php  esc_attr(the_author()); ?>">
          <?php the_author(); ?>
          </a></span></div>
        <div class="date updated"><a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( get_the_time() ); ?>">
          <?php the_time( get_option( 'date_format' ) ); ?>
          </a></div>
        <?php if ( comments_open() ) { ?>
        <div class="comments">
          <?php comments_popup_link( __( 'No Comments', 'interface' ), __( '1 Comment', 'interface' ), __( '% Comments', 'interface' ), '', __( 'Comments Off', 'interface' ) ); ?>
        </div>
        <?php } ?>
      </div>
      <!-- .entry-meta --> 
    </header>
    <!-- .entry-header -->
    <div class="entry-content clearfix">
      <?php the_excerpt(); ?>
    </div>
    <!-- .entry-content -->
    <footer class="entry-meta clearfix"> <span class="tag-links">
      <?php $tag_list = get_the_tag_list( '', __( ' ', 'interface' ) );
						if(!empty($tag_list)){
					echo $tag_list;
					
						}?>
      </span><!-- .tag-links -->
      <?php
						echo '<a class="readmore" href="' . get_permalink() . '" title="'.the_title( '', '', false ).'">'.__( 'Read more', 'interface' ).'</a>';
						?>
    </footer>
    <!-- .entry-meta --> 
     <?php } else { ?>
   </header>
		    <?php the_content();
      } ?>
  </article>
</section>
<!-- .post -->
<?php
			do_action( 'interface_after_post' );

		}
	}
	else {
		?>
<h2 class="entry-title">
  <?php _e( 'No Posts Found.', 'interface' ); ?>
</h2>
<?php
   }
}
endif;

/****************************************************************************************/

if ( ! function_exists( 'interface_child_theloop_for_page' ) ) :
/**
 * Fuction to show the page content.
 */
function interface_child_theloop_for_page() {
	global $post;

	if( have_posts() ) {
		while( have_posts() ) {
			the_post();

			do_action( 'interface_before_post' );
?>
<section id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
  <article>
    <?php 
    if( has_post_thumbnail() ) {
		$image = '';        			
		$title_attribute = the_title_attribute( array( 'echo' => false ) );
		$image .= '<figure class="post-featured-image">';
		$image .= '<a href="' . get_permalink() . '" title="'.the_title( '', '', false ).'">';
		$image .= get_the_post_thumbnail( $post->ID, 'featured', array( 'title' => esc_attr( $title_attribute ), 'alt' => esc_attr( $title_attribute ) ) ).'</a>';
		$image .='<span class="arrow"></span>';
		$image .= '</figure>';
		echo $image;
		}
do_action( 'interface_before_post_header' ); ?>
    <?php do_action( 'interface_after_post_header' ); ?>
    <?php do_action( 'interface_before_post_content' ); ?>
    <div class="entry-content clearfix">
      <?php the_content(); ?>
      <?php
    				wp_link_pages( array( 
						'before'            => '<div style="clear: both;"></div><div class="pagination clearfix">'.__( 'Pages:', 'interface' ),
						'after'             => '</div>',
						'link_before'       => '<span>',
						'link_after'        => '</span>',
						'pagelink'          => '%',
						'echo'              => 1 
               ) );
    			?>
    </div>
    <!-- entry-content clearfix-->
    
    <?php 

  			do_action( 'interface_after_post_content' );

  			do_action( 'interface_before_comments_template' ); 

         comments_template(); 

         do_action ( 'interface_after_comments_template' );

         ?>
  </article>
</section>
<?php
			do_action( 'interface_after_post' );

		}
	}
	else {
		?>
<h2 class="entry-title">
  <?php _e( 'No Posts Found.', 'interface' ); ?>
</h2>
<?php
   }
}
endif;

/****************************************************************************************/

if ( ! function_exists( 'interface_child_theloop_for_single' ) ) :
/**
 * Fuction to show the single post content.
 */
function interface_child_theloop_for_single() {
	global $post;

	if( have_posts() ) {
		while( have_posts() ) {
			the_post();

			do_action( 'interface_before_post' );
?>
<section id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
  <article>
    <?php
				if( has_post_thumbnail() ) {
					$image = '';        			
		     		$title_attribute = apply_filters( 'the_title', get_the_title( $post->ID ) );
		     		$image .= '<figure class="post-featured-image">';
		  			$image .= '<a href="' . get_permalink() . '" title="'.the_title( '', '', false ).'">';
		  			$image .= get_the_post_thumbnail( $post->ID, 'featured', array( 'title' => esc_attr( $title_attribute ), 'alt' => esc_attr( $title_attribute ) ) ).'</a>';
					$image .='<span class="arrow"></span>';
		  			$image .= '</figure>';

		  			echo $image;
		  		}
	  			?>
    <header class="entry-header">
      <?php if(get_the_time( get_option( 'date_format' ) )) { ?>
      <div class="entry-meta"> <span class="cat-links">
        <?php the_category(', '); ?>
        </span><!-- .cat-links --> 
      </div>
      <!-- .entry-meta -->
     
      <h2 class="entry-title">
        <?php the_title();?>
      </h2>
      <!-- .entry-title -->
      <div class="entry-meta clearfix">
        <div class="by-author vcard author"><span class="fn"><a href="<?php echo get_author_posts_url( get_the_author_meta( 'ID' ) ); ?>"  title="<?php  esc_attr(the_author()); ?>">
          <?php the_author(); ?>
          </a></span></div>
        <div class="date updated"><a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( get_the_time() ); ?>">
          <?php the_time( get_option( 'date_format' ) ); ?>
          </a></div>
        <?php if ( comments_open() ) { ?>
        <div class="comments">
          <?php comments_popup_link( __( 'No Comments', 'interface' ), __( '1 Comment', 'interface' ), __( '% Comments', 'interface' ), '', __( 'Comments Off', 'interface' ) ); ?>
        </div>
        <?php } ?>
      </div>
      <!-- .entry-meta --> 
    </header>
    <!-- .entry-header -->
    <?php } ?>
    <div class="entry-content clearfix">
      <?php the_content();
    		
               wp_link_pages( array( 
						'before'            => '<div style="clear: both;"></div><div class="pagination clearfix">'.__( 'Pages:', 'interface' ),
						'after'             => '</div>',
						'link_before'       => '<span>',
						'link_after'        => '</span>',
						'pagelink'          => '%',
						'echo'              => 1 
               ) );
               ?>
    </div>
    <?php if(get_the_time( get_option( 'date_format' ) )) { ?>
  </header>
  <?php } ?>

    <!-- entry content clearfix -->
    
    <?php if( is_single() ) {
					    $tag_list = get_the_tag_list( '', __( ' ', 'interface' ) );

						if( !empty( $tag_list ) ) { ?>
    <footer class="entry-meta clearfix"> <span class="tag-links">
      <?php
								echo $tag_list;?>
      </span><!-- .tag-links --> 
    </footer>
    <!-- .entry-meta -->
    <?php  }
    do_action( 'interface_after_post_content' );
						 
             }

    do_action( 'interface_before_comments_template' ); 

		comments_template();

    do_action ( 'interface_after_comments_template' );

		?>
  </article>
</section>
<!-- .post -->
<?php
			do_action( 'interface_after_post' );

		}
	}
	else {
		?>
<h2 class="entry-title">
  <?php _e( 'No Posts Found.', 'interface' ); ?>
</h2>
<?php
   }
}
endif;

/****************************************************************************************/

if ( ! function_exists( 'interface_child_theloop_for_search' ) ) :
/**
 * Fuction to show the search results.
 */
function interface_child_theloop_for_search() {
	global $post;

	if( have_posts() ) {
		while( have_posts() ) {
			the_post();

			do_action( 'interface_before_post' );
?>
<section id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
  <article>
    <?php do_action( 'interface_before_post_header' ); ?>
    <header class="entry-header">
      <h2 class="entry-title"> <a href="<?php the_permalink(); ?>" title="<?php the_title_attribute();?>">
        <?php the_title(); ?>
        </a> </h2>
      <!-- .entry-title --> 
    </header>
    <?php do_action( 'interface_after_post_header' ); ?>
    <?php do_action( 'interface_before_post_content' ); ?>
    <div class="entry-content clearfix">
      <?php the_excerpt(); ?>
    </div>
    <?php do_action( 'interface_after_post_content' ); ?>
  </article>
</section>
<?php
			do_action( 'interface_after_post' );

		}
	}
	else {
		?>
<h2 class="entry-title">
  <?php _e( 'No Posts Found.', 'interface' ); ?>
</h2>
<?php
   }
}
endif;
?>

If you need any code customization then you have to do under child theme functions.php not on the main theme.

Thank you