SimplePie_Content_Type_Sniffer::unknown

		elseif (substr($this->file->body, 0, 5) === '%PDF-')
		{
			return 'application/pdf';
		}
		elseif (substr($this->file->body, 0, 11) === '%!PS-Adobe-')
		{
			return 'application/postscript';
		}
		elseif (substr($this->file->body, 0, 6) === 'GIF87a'
			|| substr($this->file->body, 0, 6) === 'GIF89a')
		{
			return 'image/gif';
		}
		elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A")
		{
			return 'image/png';
		}
		elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF")
		{
			return 'image/jpeg';
		}
		elseif (substr($this->file->body, 0, 2) === "\x42\x4D")
		{
			return 'image/bmp';
		}
		elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00")
		{
			return 'image/vnd.microsoft.icon';
		}

		return $this->text_or_binary();
	}

	/**
	 * Sniff images
	 *
	 * @return string Actual Content-Type
	 */
	public function image()
	{
		if (substr($this->file->body, 0, 6) === 'GIF87a'
			|| substr($this->file->body, 0, 6) === 'GIF89a')
		{