How to Take screenShot or image of web page part

I Am working on facebook application. Now I want to add a feature That user can post Image of application.

I have done everything earlier means i have code for posting and for application.

But I am not able to take image of that application. Application is working on within the IFame in facebook.

So may main concern to get Image that html page that is showing in Iframe.

I have tried out lot of code snippet Nothing is working for me. Please suggest me that how can i take image of any specific part of web page.开发者_Go百科

Thanks

You could try wkhtmltoimage, which looks like it has some Windows support. Once its installed, you just run wkhtmltoimage http://www.site.com site.screenshot.png.