I’ve uploaded an updated WebGL demo I wrote some time ago. It shows a vertex displacement shader on simple models and applies some screen-space image filter (=fragment shaders) to it:

http://numb3r23.net/webgl/vertexAndImages

Here are selected screenshots:

The effects implemented are:

• Vertex shader displacement
• TwoTone shading
• CEL-Shading
• Gaussian Blur
• Image Enhancement by unsharp masking the depthbuffer
• Gamma/Contrast/Brightness adjustment