@Bubble Wow! Really? Here if I use ctrl + z fast it crashes my whole PC! Sometimes I need to wait about 5-10min or restart the machine. And it can be using small images that makes no difference for me.
@Speedstar90 , I opened a similar topic: Piskel does not overwrite the image when expected and sometimes crushes while using Ctrl + Z (undo)
And be careful using Ctrl + Z. If you use it, Piskel will save your image as a new image instead of overwriting.