Please read and follow these simple rules.

Extension Manager

404 Detector If Shimmie can't handle a request, check static files; if that fails, show a 404
Admin Controls Various things to make admins' lives easier
Alias Editor Edit the alias list
BBCode Turns BBCode into HTML
Board Config Allows the site admin to configure the board to his or her taste
Bookmarks Allow users to bookmark searches
Browser Search Allows the user to add a browser 'plugin' to search the site with real-time suggestions
Bulk Add Bulk add server-side images
Comment Word Ban For stopping spam and other comment abuse
Database Upgrader Keeps things happy behind the scenes
Downtime Show a "down for maintenance" page
Emoticon Filter Lets users use graphical smilies
Extension Manager A thing for point & click extension management
Favorites Allow users to favorite images
Handle Pixel Handle JPEG, PNG, GIF, etc files
Handle SVG Handle SVG files. (No thumbnail is generated for SVG files)
Home Page Displays a front page with logo, search box and image count
IP Ban Ban IP addresses
Image Comments Allow users to make comments on images
Image List Show a list of uploaded images
Image Manager Handle the image database
Image Ratings Allow users to rate images "safe", "questionable" or "explicit"
Image Scores (Numeric) Allow users to score images
Image Viewer Allows users to see uploaded images
Logging (Network) Send log events to a network port.
Mail System Provides an interface for sending and receiving mail.
Not A Tag Redirect users to the rules if they use bad tags
Private Messaging Allow users to send messages to eachother
Random Image Do things with a random image
Random Tip Show a random line of text in the subheader space
Regen Thumb Regenerate a thumbnail image
Report Images Report images as dupes/illegal/etc
Simple Wiki A simple wiki, for those who don't want the hugeness of mediawiki
Site Description A description for search engines
Tag Editor Allow images to have tags assigned to them
Tag List Show the tags in various ways
Update Shimmie updater! (Requires php-curl library and admin panel extension)
Uploader Allows people to upload files to the website
User Management Allows people to sign up to the website
XML Sitemap Adds sitemap.xml on request.
[Beta] Artists System Simple artists extension