src/Image.php
public function setPage($page)
    {
        $this->_page = preg_match(self::REGEX_HTML, $page) ? new File($page, '.html') : $page;
        return $this;
    }
public function setPage($page)
    {
        $this->_page = preg_match(self::REGEX_HTML, $page) ? new File($page, '.html') : $page;
        return $this;
    }
Add a page object to the output

@param string $page either a URL, a HTML string or a filename
@return static the Image instance for method chaining