Hi,
Thank you for your answer, It's true that on your picture it didn't change anything.
But I wanted to remove the Jpg artefact on a PCB (electronic) picture.
I had the feeling than the plugin I wrote was working better (and was easier to configure) on few colored images.
I attach an example (left -> original, middle -> paint net, right -> my plugin). But it's sure my plugin is really slow.
But I perhaps don't know well how to setup the original paint.net effect.
Nicolas Coquard