I was told to try white vignetting for a change. I was having a coffee break and no PC to do some serious editing. First I was puzzled how to do that "invert" vignetting on my PicSay Android software. But then I realized how simple it is. All you need to do is turn the image invert (neagative), add the vignette, and invert again.
This method can be much quicker way to do also many other tricks, even on PC editing software. For example I had only very light version of this keypad picture. So called 'Pencil Sketch' tool would not have made much change on it. But when turning it to invert, and then applying the sketch effect, it worked like a charm.
I also slowly start to understand how fun it can be play with ready made scripts. I used to think they only limit your editing into some pretty predefined results. For example so called 'faux HDR' often does the job wrong and add huge "halo effect" around the objects. But with clever combination of these scripts, one can do much more and much easier than if doing everything manually step by step.