How to download graffiti vk-io?

Question

Node.js

I'm trying to load graffiti into documents using the vk-io library with this code:

upload.documentGraffiti({
  source: 'zCx1NLcUB04.jpg'
})

But nothing works

And if you upload just as a document

upload.document({
  source: 'zCx1NLcUB04.jpg'
})

then it is loaded as file0.dat

How to correctly load a document as graffiti?