You can use the macOS Finder’s Copy command to copy and paste files. But here’s how to use the same command to copy file icons into Preview.
You’ve probably used the macOS Finder’s popup contextual menu to Copy and paste files in the Finder from one location to another in the filesystem.
To do so, you select a file or files first in the Finder, then Control-click (or right-click) the items to see the Finder’s popup contextual menu
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