Do not shows navigation thumbnail if no thumbnail is present.

tainacan-blocksy/inc/navigation.php

@@ -61,23 +61,23 @@ if ( !function_exists('tainacan_blocksy_get_adjacent_item_links') ) {
 				$next_thumb = get_the_post_thumbnail_url( get_next_post(), 'tainacan-medium' );
 			}
 
-			$previous_post_image_output = blocksy_simple_image(
+			$previous_post_image_output = $previous_thumb ? blocksy_simple_image(
 				$previous_thumb,
 				[
 					'inner_content' => '<svg width="20px" height="15px" viewBox="0 0 20 15"><polygon points="0,7.5 5.5,13 6.4,12.1 2.4,8.1 20,8.1 20,6.9 2.4,6.9 6.4,2.9 5.5,2 "/></svg>',
 					'ratio' => '1/1',
 					'tag_name' => 'figure'
 				]
-			);
+			) : '';
 
-			$next_post_image_output = blocksy_simple_image(
+			$next_post_image_output = $next_thumb ? blocksy_simple_image(
 				$next_thumb,
 				[
 					'inner_content' => '<svg width="20px" height="15px" viewBox="0 0 20 15"><polygon points="14.5,2 13.6,2.9 17.6,6.9 0,6.9 0,8.1 17.6,8.1 13.6,12.1 14.5,13 20,7.5 "/></svg>',
 					'ratio' => '1/1',
 					'tag_name' => 'figure'
 				]
-			);
+			) : '';
 				
 		}
 
@@ -187,7 +187,6 @@ if ( !function_exists('blocksy_default_post_navigation') ) {
 		ob_start();
 
 		?>
-
 			<nav class="<?php echo esc_attr( $container_class ); ?>">
 				<?php if ($next_post): ?>
 					<a href="<?php echo esc_url(get_permalink($next_post)); ?>" class="nav-item-prev">
@@ -290,7 +289,6 @@ if ( !function_exists('tainacan_blocksy_item_navigation') ) {
 			];
 			
 			$adjacent_links = tainacan_blocksy_get_adjacent_item_links();
-	
 			$previous = $adjacent_links['previous'];
 			$next = $adjacent_links['next'];
 		}