Block or remove pages using a robots.txt

[semer]

I want to use robots.txt to prevent googlebot access the specific folder on the server,

Please tell me if the syntax below is correct

User-Agent: Googlebot Disallow: /folder/

I want to use robots.txt to prevent google image index the images of  my website  ,

Please tell me if the syntax below is correct

User-agent: Googlebot-Image

Disallow: /

[OlegKorneitchouk]

Yes, that is correct.

Once you have it set up, you can test what pages are blocked in your GWT account. Health > Blocked URLs > select which bot you want to test at the bottom of the page.

Resources:

Google's bots - http://support.google.com/webmasters/bin/answer.py?hl=en&answer=1061943

WMT Blocked URL testing - https://www.google.com/webmasters/tools/robots-analysis