add page for virtual copies

content/howto/virtual-copy.md

@@ -0,0 +1,16 @@
+---
+title: make a virtual copy of an image
+id: virtual-copy
+weight: 50
+draft: false
+author: "people"
+---
+
+darktable calls multiple developments of a single image "duplicates".  You
+can create, remove, or name them using the
+_duplicate manager_](../module-reference/utility-modules/darkroom/duplicate-manager.md)
+in [_darkroom_](../darkroom/darkroom-view-layout.md) view, and you can
+create duplicates by selecting one or more images in the lighttable
+and clicking on the _duplicate_ button in the
+[_actions on selection_](../module-reference/utility-modules/lighttable/selected-image.md)
+module.