Get a image for a course from the course summary files

courseimages.php

<?php

require_once("config.php");

function course_image($courseid) {
    global $DB, $CFG;

    require_once($CFG->libdir. '/coursecatlib.php');
    
    $courserecord = $DB->get_record('course', array('id' => $courseid));
    $course = new course_in_list($courserecord);

    foreach ($course->get_course_overviewfiles() as $file) {
        $isimage = $file->is_valid_image();
        $url = file_encode_url("$CFG->wwwroot/pluginfile.php",
            '/'. $file->get_contextid(). '/'. $file->get_component(). '/'.
            $file->get_filearea(). $file->get_filepath(). $file->get_filename(), !$isimage);
        if ($isimage) {
            return html_writer::empty_tag('img',
                array('src' => $url, 'alt' => 'Course Image '. $course->fullname, 'class' => 'courseimage'));
        } 
    }
}

// Echo the course image for course with id number 77
echo course_image(77);