Hi
Your screenshot is not showing up, anyway.. interesting question, I took at look at the config but it does not seem like you can scale the cursor in the program alone. I just tried on mac, if you increase the size of your curser in general, then the cursor in PyxelEdit should scale aswell. I recall that windows too also has a mouse size property in the control panel, try to change that and see it is works.
I hope it helps :)