Allow Contributors to Upload Images

add_filter( 'user_has_cap', function ( $allcaps, $caps, $args, $user ) {

	if ( in_array( 'contributor', $user->roles ) && empty( $caps['upload_files'] ) ) {

		$allcaps['upload_files'] = true;

	}

	return $allcaps;

}, 10, 4 );