Restrict instructors to upload course images of particular sizes while creating new courses

upload-file-size.php

<?php
add_filter( 'ld_dashboard_course_form_fields', function( $fields ) {
	if( ! empty( $fields ) ) { //First we check fields are not empty

		foreach ( $fields as $key => $field ) {
			if( 'field_61fcef414383d' === $fields[$key]['key'] ){
				$fields[$key]['max_width'] = 600; //Provide the value of maximum with of image that would be uploaded by instructor
				$fields[$key]['max_height'] = 600; //Provide the value of maximum height of image that would be uploaded by instructor
				$fields[$key]['max_size'] = 600; //Provide the value of size of image that would be uploaded by instructor
			}
		}
	}

	return $fields;
} );
?>