How to draw a mask image

[baiyu001]

Thank you again for your contribution. I have a few questions and hope you can help me answer them:

1. I see that you have provided a link to the tool for drawing mask images, but I find that this link does not seem to work, could you please check it again?
2. What if I want to draw an arbitrary mask image on an arbitrary image? How do I get an arbitrary mask.png? Looking forward to your reply!