Hide portion of image using css/javascript

Hi I have been trying to trying to hide a portion of image for my blog. Basically what I would lik开发者_JAVA百科e to do is to have images of different sizes (or same width but different heights) on my blog's single post page. But on the main page of the it should show only a portion of it, the size of the visible image should be same for all the images.

I hope the above is clear, just in case I the above explanation is not clear here is a site that works on similar way http://www.creativeapplications.net/

Now I could not get if it's done using CSS or some sort of Javascript. Could you guys help me to understand it and achieve similar image effect.

Thank you Takias

You want CSS' clip property: http://www.seifi.org/css/creating-thumbnails-using-the-css-clip-property.html