Automaticly copies the image and insert this. The script creates a Layer-Mask and makes a part of the insert layer invisible.
It's great to have a part of the original image on the top, because than you have a very well comparision.
If you have any suggestions for improvement contact me.
Please notice: It's only version 1.0.0, so I hope it will be better in near future!
I hope this example conform your requests: