Drawingboard.js
A canvas based drawing app that you can integrate easily on your website.
Im.js
Image Match - Project to allow compare different images pixel by pixel with good performance
Liquidfun
2D physics engine for games
Color
JavaScript color conversion and manipulation library
Obelisk.js
JavaScript Engine for Building Isometric Pixel Element with HTML5 Canvas
Jcrop
Jcrop (official) - Image Cropping Plugin for jQuery
Ocanvas
JavaScript library for object-based canvas drawing.
Gif.js
JavaScript GIF encoding library
Img to Ascii
A JavaScript implementation of a image to Ascii code
Cropper
A simple jQuery image cropping plugin.
Focal Point
A small set of CSS classnames to help keep images cropped on the focal point for responsive designs. Using only HTML/CSS, web authors can specify an image's focal point, which stays as the image's primary focus, while the image's available width changes on responsive webpages. Crop and re-size images depending on available width and let CSS to do all of the work, and without any JavaScript.
Kinetic Js
KineticJS is an HTML5 Canvas JavaScript library that extends the 2D context by enabling canvas interactivity for desktop and mobile applications.
Easel JS
The Easel Javascript library provides a full, hierarchical display list, a core interaction model, and helper classes to make working with the HTML5 Canvas element much easier.
Breathing Halftone
Images go whoa with lots of floaty dots
Html2canvas
Screenshots with JavaScript
Paper.js
The Swiss Army Knife of Vector Graphics Scripting – Scriptographer ported to JavaScript and the browser, using HTML5 Canvas. Created by @juerglehni & @jonathanpuckey
jQuery QR Code
qrcode generation standalone (doesn't depend on external services)