Images do not get included

[jgebal]

Hello,
First of all, thank you for amazing plugin - it simplifies efforts of integrating multiple sites into one.

I ran into an issue and don't know how to solve this.

I'm publishing a readme from a project on the main Org website.
The content of the MD file is:

---
title: utPLSQL-PLSQL-Developer plugin
---

{%
  include-markdown "https://raw.githubusercontent.com/utPLSQL/utPLSQL-PLSQL-Developer/develop/README.md"
  rewrite-relative-urls=true
%}

The problem is however that images are not embedded correctly.
They are linked as:

<img alt="Tools Ribbon" src="https://www.utplsql.org/https:/raw.githubusercontent.com/utPLSQL/utPLSQL-PLSQL-Developer/develop/screenshots/tools_ribbon_full.png">

The README.md file is referencing images as:

![Tools Ribbon](screenshots/tools_ribbon_full.png)

How can I fix this problem?