I tried to look in the internet, but every question and topic was about improving quality of animated GIF, however it is not in my case.
What I have is static image with 256 colors, it is saved in PNG format, but it seems like it originally was saved in GIF, because every gradient is suffered from heavy dithering.
I want to improve quality of image and get rid of dithered gradients.
Do you have something in mind what I can use to make gradients look like they supposed to do, in other words revert dithering and make smooth gradients again?
I have many images. There is 3 example areas which was affected with dithering:
EDIT: Forget to mention beforehand, that other part of image are detailed, so I provide more examples both with dithering and details:
dithered gradient in detailed area: