In after effects, there is a very powerfull functionanlity called Snapshot. ( the little camera, and the little guy next to RGB and alpha channel bouton )
You can snapshot the image by clicking " the little camera ", change all the effects you want and then, click on " the little guy bouton " to see the exactly image when you take the snapshot.
This is very usefull to compare easily and rapidely 2 images
But it miss this functionality in fusion !!!
Do you know a script to do that ? or a method do to that in Fusion ? ( i know channel A or B in fusion, but this is not very pratical. )
Thx !