First, thank you so much for open-sourcing this awesome app 👍

This is a feature request and not an issue. I did ask for this in orgzly g+ page.

Here is a little reference video for org attachments:
https://www.youtube.com/embed/KMlp9HUJI3s?ecver=1

My basic use case is using the phone camera to capture a picture of a document and attaching it to a task. Similar to what you can do with evernote, for example. Here is a video of this feature in evernote in action:
https://youtu.be/QGj7Sq0Qlxk?t=58

Cheers!