Blocking Google From A Certain Page

Hey guys, I have a plan but I don't know how safe it will be.

I have a blog with adsense running on it but I want to implement a image section to the site. The problem is that it's of course going to be duplicate content and I run the risk of getting penalties.
However, I plan to start a separate wordpress install solely for the pictures and it won't have adsense on it.
It's going to be mysite.com/images and my plan is to block that URL via robots.txt

My question is, have I avoided the risk of duplicate content penalties? In terms of the SERPS and Adsense?

I just visited 10 Halloween Wallpaper site's. 8 of them had the same content,pretty much.
as far as I can say, you should be safe,since the robots.txt files not getting read!! which is the idea of google does not want to know/crawl.
will follow for better information,good question op

Use a decent cloaker and serve any other content you like.