I have a large catalog import where the items often refer to a single common image (such as "brand_logo"). When I import the images via CSV parser, if the item refers to the same image file, an incremented duplicate is created.
Example: Using the example files supplied with the module, I modified 2 books to use the same image file, which are imported to files/field/image/
as 51JQbhO0MmL.jpg
and 51JQbhO0MmL_0.jpg
.
This causes the images directory to balloon to 20 times the size it should be (lots of shared images).
Honestly, what I would prefer to do is to upload the images to the site separately (manually, via FTP etc.) and just import the links to the images, but I haven't figured that one out either.
(The data (files) is not being replicated, just the images are replicated.)