Category Image in Post

I would like to include category-specific images with the titles of my posts.

Click here to see what my goal is.

I followed these directions and put the following code

<?php foreach((get_the_category()) as $cat)
 { echo '<img src="https://www.yorkrules.com/yorkrules3/global/images/categoryIcon/' . $cat->cat_ID . '.jpg"
alt="' . $cat->cat_name . '" />'; } ?>

into the index.php as follows

<div class="contenttitle">
<?php foreach((get_the_category()) as $cat)
 { echo '<img src="https://www.yorkrules.com/yorkrules3/global/images/categoryIcon/' . $cat->cat_ID . '.jpg"
alt="' . $cat->cat_name . '" />'; } ?>
	<h1><a href="<?php the_permalink() ?>" rel="bookmark"><?php the_title(); ?></a></h1>
	<?php the_time('F j, Y'); ?> | <?php comments_popup_link('Leave a Comment', '1 Comment', '% Comments'); ?>

	</div>
	<?php the_content(__('Read more'));?>
	<!--
	<?php trackback_rdf(); ?>
	-->

	<?php endwhile; else: ?>

I also saved the category-specific images in the ‘categoryIcon’ folder, named after their related category IDs (e.g. ‘4.jpg’ for the ‘look’ category, which is ID 4).

Unfortunately, I saw no effect on my posts.

Not being familiar with PHP, perhaps I haven’t correctly modified the PHP code? Any ideas or advice would be greatly appreciated.

Thanks,

York