wp-includes/class-wp-image-editor-gd.php:39Checks to see if current environment supports GD.
$argsarrayoptionalarray()bool public static function test( $args = array() ) { if ( ! extension_loaded( 'gd' ) || ! function_exists( 'gd_info' ) ) { return false; } // On some setups GD library does not provide imagerotate() - Ticket #11536. if ( isset( $args['methods'] ) && in_array( 'rotate', $args['methods'], true ) && ! function_exists( 'imagerotate' ) ) { return false; } return true; }Introduced in 3.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-image-editor-gd.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.