In IIS7 I\'ve got the ability to set caching options. These options are added to my web.config as such...
The main difference is that
the first is for server-side caching of dynamic output such as aspx pages (basically keeps the page output in memory for subsequent requests). As @artem-vertiy's answer points out, using it for static content makes no sense.
the second one is 'internet-side' : it is implemented by writing standard response headers, it tells both client browsers and public proxies how to manage cached files.