Images not rendered with KnpSnappyBundle/wkhtmltopdf from HTML to PDF

Question

Images are not rendered when trying to generate pdf from html, even if the path to the image is right.

In my html template:

<img style="width: 100%;" src="{{pathToWeb ~ asset('images/my_image.png') }}">

config.yml:

twig:
    debug: '%kernel.debug%'
    strict_variables: '%kernel.debug%'
    form_themes: ['bootstrap_4_horizontal_layout.html.twig']
    globals:
        pathToWeb: "%kernel.project_dir%/web"

EDIT: If you downvote the question and find it stupid, at least explain why

---

For some reason, only png images with at least 1 transparent pixel are rendered, i have no idea why it works this way but it works. Jpg images won't show up at all.