Saves image to file.

function wp_save_image_file( $filename, $image, $mime_type, $post_id ) {
	if ( $image instanceof WP_Image_Editor ) {

		/** This filter is documented in wp-admin/includes/image-edit.php */
		$image = apply_filters( 'image_editor_save_pre', $image, $post_id );

		/**
		 * Filters whether to skip saving the image file.
		 *
		 * Returning a non-null value will short-circuit the save method,
		 * returning that value instead.
		 *
		 * @since 3.5.0
		 *
		 * @param bool|null       $override  Value to return instead of saving. Default null.
		 * @param string          $filename  Name of the file to be saved.
		 * @param WP_Image_Editor $image     The image editor instance.
		 * @param string          $mime_type The mime type of the image.
		 * @param int             $post_id   Attachment post ID.
		 */
		$saved = apply_filters( 'wp_save_image_editor_file', null, $filename, $image, $mime_type, $post_id );

		if ( null !== $saved ) {
			return $saved;
		}

		return $image->save( $filename, $mime_type );
	} else {
		/* translators: 1: $image, 2: WP_Image_Editor */
		_deprecated_argument( __FUNCTION__, '3.5.0', sprintf( __( '%1$s needs to be a %2$s object.' ), '$image', 'WP_Image_Editor' ) );

		/** This filter is documented in wp-admin/includes/image-edit.php */
		$image = apply_filters_deprecated( 'image_save_pre', array( $image, $post_id ), '3.5.0', 'image_editor_save_pre' );

		/**
		 * Filters whether to skip saving the image file.
		 *
		 * Returning a non-null value will short-circuit the save method,
		 * returning that value instead.
		 *
		 * @since 2.9.0
		 * @deprecated 3.5.0 Use {@see 'wp_save_image_editor_file'} instead.
		 *
		 * @param bool|null        $override  Value to return instead of saving. Default null.
		 * @param string           $filename  Name of the file to be saved.
		 * @param resource|GdImage $image     Image resource or GdImage instance.
		 * @param string           $mime_type The mime type of the image.
		 * @param int              $post_id   Attachment post ID.
		 */
		$saved = apply_filters_deprecated(
			'wp_save_image_file',
			array( null, $filename, $image, $mime_type, $post_id ),
			'3.5.0',
			'wp_save_image_editor_file'
		);

		if ( null !== $saved ) {
			return $saved;
		}

		switch ( $mime_type ) {
			case 'image/jpeg':
				/** This filter is documented in wp-includes/class-wp-image-editor.php */
				return imagejpeg( $image, $filename, apply_filters( 'jpeg_quality', 90, 'edit_image' ) );
			case 'image/png':
				return imagepng( $image, $filename );
			case 'image/gif':
				return imagegif( $image, $filename );
			case 'image/webp':
				if ( function_exists( 'imagewebp' ) ) {
					return imagewebp( $image, $filename );
				}
				return false;
			default:
				return false;
		}
	}
}