Pixelmator Pro is like a deluxe alternative to Microsoft Paint its all done without much of the features you can ohotoshop powerful, even compared to.
If you think there is a better way to do this, please let me know using the Contact page on this site. A forum where Apple customers help each other with their products. Our only real complaint is that Pixelmator does tend to just throw features onto the screen and then leave you to figure out how everything works. These programs have been designed to combine different layers of graphics to create new photos.