Hi guys,
Recently I've been trying to learn 'dithering' technique.
Im using Photoshop CS and Im a noob with this pixel art.
Could anyone explain how to perform this dither?

Does this 'dithering' done using gradient tool or you guys do it manually (pixel by pixel)?
Is there some kind of brush to do this quicker?

Does this 'dithering' can only be seen in GIF format, 'coz i dont see any 'dithering' in PSD format.
Am I doing it right? I dont understand

I appreciate any kind of help.
Thanks a million :>