Add a custom scratch card template from your theme.

mycred-scratch-card-templates-filter-example1

/**
 * Add Custom Scratch Card Template
 * @since 1.0
 * @version 1.0
 */
function mycred_add_custom_scratch_card_template( $templates ) {

	$templates['mytemplate'] = array(
		'label'               => 'My Custom Template',
		'minimum_scratch'     => 75,
		'brush_diameter'      => 15,
		'card_width'          => 300,
		'card_height'         => 400,
		'coin_image'          => get_template_directory_uri() . '/images/card/coin.png',
		'cover_image'         => get_template_directory_uri() . '/images/card/cover-image.png',
		'buy_log'             => '', // optional
		'win_log'             => '', // optional
		'win_message'         => '', // optional
		'setup'               => array(
			array(
				'number'         => 100,
				'value'          => 0,
				'attachment_ids' => array(
					get_template_directory_uri() . '/images/card/nowin.png'
				)
			),
			array(
				'number'         => 10,
				'value'          => 10,
				'attachment_ids' => array(
					get_template_directory_uri() . '/images/card/10points.png'
				)
			)
		)
	);

	return $templates;

}
add_filter( 'mycred_scratch_card_templates', 'mycred_add_custom_scratch_card_template' );