Automattic just released a collection of plugins as one “super-plugin” called Jetpack. As they explained it, the goal was to bring eight of the most requested features available on WordPress.com to the millions of self-hosted WordPress sites in one easy-to-install curated package. If you use JetPack Stats on your site (formerly released as a stand alone plugin called WordPress.com stats), you may be familiar with the smiley face image that it adds to the bottom of every page on your site.

Installing too many plugins will make the wordpress blog work slowly and unstable, use code built in your theme will reduce the system resources. I’ve known a ton of plugins and widgets that allows me to list recent comments and recent post on my WordPress blog but I’m not using it because I’ve integrated some useful code below then I get results similar to those extensions which I’ve known.

From WordPress 2.5, the Gallery feature allows the option to add an image gallery to a Post or Page on your WordPress blog.
Upload all your photos and simply type the shortcode [gallery in a post or page to display a thumbnail gallery of images attached to that post or page. Clicking on a thumbnail image will open either the original image or a larger image in a separate Attachment page.