I have a set of about 200 PNG-images in like that:
Only black and white, no colors, no grey.
I need the background color (white) to be removed and tried to do so in macOS Preview (with that Instant alpha tool), but the problem is that it just lets me remove connected white areas. But I also want to remove white between the lines and inside the note circle.
In short: every black pixel should stay black, every white pixel should be transparent. How can I do this without selecting every white area? I have mac Preview and GIMP, but other Freeware is possible too.
And the other thing: It is not a single image, but about 200 of that kind. Is there any way to automate the operation? E.g. with the GIMP Batch mode? (I have got no clue how to use it.)
PS: Is that question right on graphicdesign? I had no idea where to look else...