First issue, the saving. You can use JFileChooser to show a save dialog for you. After the user hits Save, the showSaveDialog method will return JFileChooser.APPROVE_OPTION. If this is the return value, get the selected File, and use ImageIO.write to save the image to a file.
As for the second issue, that's going to be tricky with direct image manipulation. Fortunately, BufferedImage can help you out:
Although I drew your original image, you can also use BufferedImage's setRGB method to set each pixel directly. That way you don't need the original image at all.
There are no new questions, but there may be new answers.
Joined: Sep 11, 2009
OK, so I'm going to post a new message on the other forum. And thank you again Rob Spoor for your very useful answer. In the future I'm going to write links to the other forum in case of crossposting or even avoid crossposting at all.