Real vintage computing aficionados prefer a KryoFlux disk image, it's magnetic flux transitions produce a warmer image and hits the high photoreceptor notes in your retina.

An original file would be the same file byte for byte in the original obsolete image format for example ILBM/IFF.

An exact copy would be a lossless PNG (for example) of the image, that you wouldn't be able to tell the difference by looking at it when it's displayed on a screen from the original.

I think they mean the original amiga files, not the nft image which obviously right click save is the same as buying it .

Theft. But, ianal.