Just an update, it works fine. I almost feel silly for asking I use XnView to grab screenshots on my PC and the native screen-capture Command+Shift+3 on my Mac.

I do miss frame-step capabilities though. In MPC-HC (where I make most of my captures) I always frame-step forward and backward to get the perfect shot of a vehicle. With Netflix streaming you have to be fast with the spacebar! And then, if you miss the shot, you have to rewind and wait for the HD footage to buffer again