Owl-Carousel: how to fit to the real image size?

to “fake” a lighslider ( I tried to insert it in my page as written in the GitHub readme but unsuccesfully) I’m trying to use the owl-carousel with an html code extracted from the hero twig:

[owl-carousel items=1 autoplay=true loop=true]
<section class="section hero hero-small" style="background: url({{ page.media['image-1.png'].url }});background-size: cover;color:#fffff0;font-size: bold;">
<section class="container grid-md" style="text-align: center;">
<q>Amiamo… non nelle grandi, ma nelle piccole cose fatte con grande amore. C'è tanto amore in tutti noi, non dobbiamo temere di manifestarlo.</q><br/>
<small class="author">Madre Teresa di Calcutta</small>
</section>
</section>
<section class="section hero hero-small" style="background: url({{ page.media['image-2.png'].url }});background-size: cover;color:#fffff0;font-size: bold;">
<section class="container grid-md" style="text-align: center;">
<q>C'è molta sofferenza in giro, davanti alla quale la gente chiude gli occhi, non sempre pronta ad accogliere e capire, piuttosto pronta a ferire, a deridere ed etichettare…</q><br/>
<small class="author">Silvia Bon</small>
</section>
</section>
[/owl-carousel]

I cannot understand why, also if my images are 964 x 250 the carousel is 856 x 373.
Do you know a way to avoid that and made the carousel 250px in height ( width is not so foundamental :frowning: )