CODE EXAMPLE FOR PHP

moodle get course image

// Create a course_in_list object to use the get_course_overviewfiles() method.
require_once($CFG->libdir . '/coursecatlib.php');
$course = new course_in_list($course); //don't send the id jsut send the whole course if not you will get the stcClass Error

$outputimage = '';
foreach ($course->get_course_overviewfiles() as $file) {
    if ($file->is_valid_image()) {
        $imagepath = '/' . $file->get_contextid() .
                '/' . $file->get_component() .
                '/' . $file->get_filearea() .
                $file->get_filepath() .
                $file->get_filename();
        $imageurl = file_encode_url($CFG->wwwroot . '/pluginfile.php', $imagepath,
                false);
        $outputimage = html_writer::tag('div',
                html_writer::empty_tag('img', array('src' => $imageurl)),
                array('class' => 'courseimage'));
        // Use the first image found.
        break;
    }
}
echo $outputimage;