User-agent: Mediapartners-Google* 
Disallow: /images/
Disallow: /photos/
Disallow: /covers/

User-Agent: * 
Disallow: /images/
Disallow: /photos/
Disallow: /covers/

User-agent: ia_archiver
Disallow: /images/
Disallow: /photos/
Disallow: /covers/