User-agent: Googlebot
Disallow: /*.gif$

User-agent: Googlebot
Disallow: /*.jpg$

User-agent: Googlebot
Disallow: /*.png$

User-agent: Googlebot
Disallow: /*.pdf$

User-agent: Googlebot
Disallow: /*.doc$

User-agent: Googlebot
Disallow: /*.txt$