How can I import data files to pass image URL to data value in the Collection Runner?

I’m testing an API with POST method to register a user.
The register API requires some information. So I added set of keys in form-data in Body.
There are about 8 - 9 key with text type and 1 key with file type. You can see image 1 below.

I want to test several set of keys so I import external json file.
With importing external json file, I can pass the value of text type keys. But can’t import with file type key (image key).


External json file can’t pass file URL into the value.

So how can I import file URL value from external file?