@leG, The ‘Shortcode Owl Carousel’ plugin processes a certain tag/shortcode inside the Markdown page. And your Twig code is not being processed inside Markdown… A catch-22 it seems…
Fortunately, Twig processing inside Markdown can be enabled by setting the following in frontmatter (docs):
process:
twig: true
Then you can mix Twig inside your markdown page as follows:
---
title: My Owl carousel
process:
twig: true
---
[owl-carousel items=1 nav=true]
<img src="{{ page.media['image-1.jpg'].url }}">
<img src="{{ page.media['image-2.jpg'].url }}">
[/owl-carousel]
Hope this helps…