What is the best method to have custom placeholder images?

I attempted to put it here but it isn't working:

/templates/zenbase/html/com_k2/images/placeholder/category.png

Try to put them in /templates/zenbase/images/placeholder/category.png

That worked. I was following the same override logic as com_k2 templates like /templates/zenbase/html/com_k2/templates/drums

Learned something new today!

That path works only for the template files and not css or images.