Handling custom link types for html export in v 9.0 - Replacement for deprecated `org-add-link-type`?

[Milan Zimmermann <milan.zimmermann@gmail.com>]

Hi:

I have a question about how to define custom link type, which before
9.0 used the (9.0) deprecated  `org-add-link-type`.

1. Let me first provide the context:

There is often a need to generate, for org links export/publish to
Html, elements where img src URL starts with a slash, like this

<img src="/images/a.jpg" >

The only way that was possible before v9, for this to be exported from
a link such as

[[/images/a.jgp]]

was to use a method described in

http://stackoverflow.com/questions/14684263/how-to-org-mode-image-absolute-path-of-export-html

- Basically, the solution described there is

a) define a custom link type such as "img"
b) in org,  use [[img:images/a.jpg]]
c) define two functions handling the img link in org and on
export/publish, and call (org-add-link-type "img"
'org-custom-link-img-follow 'org-custom-link-img-export)

2. The problem and question

In org 9.0, we get `org-add-link-type ... This function is obsolete
since Org 9.0 use `org-link-set-parameters' instead.

My problem is I have no idea how to, in a practical sense, use
`org-link-set-parameters` to define a custom link type "img" and
handle it's image handling in both org buffer and Html publish.

My question is, are there any links and examples how one would do the
above in 9.0?

Thanks
Milan