ThumbBase::fileExistsAndReadable PHP Method

    protected function fileExistsAndReadable()
    {
        if ($this->isDataStream === true) {
            return;
        }
        if (stristr($this->fileName, 'http://') !== false) {
            $this->remoteImage = true;
            return;
        }
        if (!file_exists($this->fileName)) {
            $this->triggerError('Image file not found: ' . $this->fileName);
        } elseif (!is_readable($this->fileName)) {
            $this->triggerError('Image file not readable: ' . $this->fileName);
        }
    }