How to check if we save with iptc option

[snowforest]

For the last item, filing to copyright office for my book, which includes the images I made is also a good protection right? Because most my images are not very complicated ones I draw myself using librecad etc... and cropping doesn't mean much (someone can add the lines to the sides of the image)

And about the thing you mention about layers, so I should put empty layer onto my image and save like that even if it is redundant?

also does it help to put copyright as a Jpeg "comment", as you suggested or that means nothing?