[giulio]

Thinking of how an art program might blur an image, I came up with a rather simple sounding solution. Replot the same image off-center with a certain amount of opacity many times. With that solution, why couldn't it be done with javascript? It can! Take a look...
View the Javascript based real-time blur demo

Un-useful, impractical, but fun!

[Aptmunich]

Cool idea Giulio...

Might be a cool effect for images if you were to automatically "animate" the blur going from very blurred to not blurred...