Auto Mask is a Sketch plugin that merges simplicity and power, giving you precise control over your image masks. Select a single layer or group, hit CMD+SHFT+M and you now have a mask group ready to be customized.
The plugin is also available on GitHub: https://github.com/patrickhill/SketchAutoMask
This plugin is free to use and share but you can kindly support further development, a.k.a. buy me a beer, through PayPal below.
Designed and built by HelloHill.