How to access attachments

Hey so I can see the endpoint to access attachments but I fail to see how I can download or find a URL for those attachments.
IE I would like to display the invoices and photos from a job card in my app.

I am able to display a newly created invoice by capturing the image returned from the api call, however this I want grab the images that are already in the diary.

Also I would like to be able to send invoices and photos in an email via servicem8

What options do I have here