Image matching tool: To me Headshot SHIFT+Q is kind of difficult to handle. The opacity slider makes of course the original
shine half way through, but its quite difficult to clearly see the difference, at least in my case.

To improve this i have the following suggestion:
Make it blink. - Built in an additional LFO (low frequency oscillator) that switches constantly beetween on and off following a user defined time value.
Lets say somewhere beetween 10 times a second and every 2 or 3 seconds.
Unfortunately i can not simulate this, but i bet this could be a huge improvement on the matter.
Try it out !