IIS server images and external url caching

Hi to all,

I am new to windows hosting.My client site is hosted on windows server with IIS server but the page load speed is slow because of the some external url and large images for the slideshow.

For example this link taking 1.56s to load


We have to load this image from the external server because we are using some thirdparty script.

How we can cache this image and other using web.config

Secondly we are using some facebook module following url issue is when checking speed it show defer parsing of javascript how we can handle this