@gen035 Thanks for the clarification.
Looking at the code snippet from your first post I notice there are a few syntax issues. Quoting the Twig docs:
The first filter returns the first "element" of a sequence, a mapping, or a string.
I presume the value of 'logo' in '/user/config/site.yaml' is a string containing the filename of the logo. The function 'first' in {{ site.logo | first.path }} will, according its function, therefor return the first character of the name of the logo file.
Furthermore, because the result of 'first' is a string it has no property/method 'path' defined. Also, if 'first' would have returned an image, the property 'url' should be used instead of 'path'.
Solution:
If the property 'logo' in 'site.yaml' only contains the filename and no path, the code returning the correct path would be:
<img src="{{ theme_url }}/images/{{ site.logo }}" alt="La Bete" class="header-logo"/>
- or -
<img src="{{ url('theme://images/'~site.logo) }}" alt="La Bete" class="header-logo"/>
Hope this helps...