How to show category image if no featured image is set?

Question

Can I do this for posts?

I have the most recents posts I am fetching and I am showing the thumbnail (the featured image) of these posts IF they exist.

What I want to do now, is to show category images IF the featured image does not exist.

Can someone help me with this?

I have this, at the moment:

    <?php 

    $args = array( 'numberposts' => '5' );
    $recent_posts = wp_get_recent_posts($args);
    $category = get_the_category(); 
    foreach( $recent_posts as $recent ){
        if($recent['post_status']=="publish"){
        if ( has_post_thumbnail($recent["ID"])) {
            echo '<a href="' . get_permalink($recent["ID"]) . '" title="Look '.esc_attr($recent["post_title"]).'" >' .   get_the_post_thumbnail($recent["ID"], 'thumbnail').'<div class="browse_category_name"> ' . $recent["post_title"]. '<div> ' . get_the_author_meta('display_name', $recent["post_author"]). '</div></div></a></li> ';
        } else{
            echo '<a href="' . get_permalink($recent["ID"]) . '" title="Look '.esc_attr($recent["post_title"]).'" >' .  get_categories_with_images($post->ID,' ,') . $recent["post_title"].'</a></li> ';
        }
         }
    }
    ?>

And this is my functions.php:

function get_categories_with_images($post_id,$separator ){

    //first get all categories of that post
    $post_categories = wp_get_post_categories( $post_id );
    $cats = array();

    foreach($post_categories as $c){
        $cat = get_category( $c );
        $cat_data = get_option("category_$c");

        //and then i just display my category image if it exists
        $cat_image = '';
        if (isset($cat_data['img'])){
            $cat_image = '<img src="'.$cat_data['img'].'">';
        }
        $cats[] =  $cat_image . '<a href="'.get_category_link( $c ) . '">' .$cat->name .'</a>';
    }
    return implode($separator , $cats);
}

Problem: category image is not shown, even though thumbnail / featured image is not set.

Answer 1

You have a typo. In your loop you're checking has_post_thumbnail($recent["ID"]), but $recent['ID'] won't be set because the variable for each post in your foreach is $decent:

foreach( $recent as $decent ){

Answer 2

Change your code to :

<?php 

$args = array( 'numberposts' => '5' );
$recent = wp_get_recent_posts($args);
$category = get_the_category(); 
foreach( $recent as $decent ){
    if($decent['post_status']=="publish"){
    if ( has_post_thumbnail($decent["ID"])) {
        echo '<a href="' . get_permalink($decent["ID"]) . '" title="Look '.esc_attr($decent["post_title"]).'" >' .   get_the_post_thumbnail($decent["ID"], 'thumbnail').'<div class="browse_category_name"> ' . $decent["post_title"]. '<div> ' . get_the_author_meta('display_name', $decent["post_author"]). '</div></div></a></li> ';
    } else{
        echo '<a href="' . get_permalink($decent["ID"]) . '" title="Look '.esc_attr($decent["post_title"]).'" >' .  get_categories_with_images($post->ID,' ,') . $decent["post_title"].'</a></li> ';
    }
     }
}
?>

The post is now $decent, not $recent