User-agent: * 
Disallow: /administrator/
Disallow: /cache/
Disallow: /editor/
Disallow: /help/
Disallow: /includes/
Disallow: /language/
Disallow: /modules/
Disallow: /installation/
Allow: /images/
Allow: *.jpg
Allow: *.png

User-agent: Googlebot-Image
allow: /images/