I have a bunch of png with a different text each, which I will use for many stuff, mostly to paste it into some documents, like a kind of "water mark", but it will also be used for some "dinamic" stuff, I want it to be like some dot matrix with transparency, but some parts where I'm going to use it don't allow "opacity", so how can I make an image into a dot matrix so it "appears to be a water mark"?
TLDR: how can I make an image into a transparent dot matrix for free (no pirated stuff, please).