I've come a bit late to this thread, but it overlooks what is in my opinion an even better solution - Default Folder X (though it's not free). Among many other features, it can place a panel at the bottom of Open dialogs with options to show selected file and folder Previews, Information (where you can add or remove a label, hide or show the file extension, lock or unlock the file and change its stationary status), Comments (which you can edit) and Permissions (which you can change). If you hover over an item preview the Quick Look full-screen arrows appear, enabling you to enlarge the view with a click. No drag and drop required. And though the Space bar won't dismiss the enlarged view, the Escape key will as will clicking on the image. All in all a very slick solution to the problem at hand.

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WhiteDog

Don't anthropomorphize computers.
They hate that.