Set explicit width and height for image for Lighthouse

[nastic]

Hi,

I am having an issue with my product images. The lighthouse report always says that my images do not have an explicit width and height and additionally I think they lazy loaded in a place where they shouldn't be, as the product image is immediate,y visible to the customer.  

I am afraid, that when I add lets 500px to the height part in the code, that it won't be responsive on mobile (and mobile first is whats counts here).

Here is the code, maybe somebody can tell me how to fix it:

 Every help help is greatly appreciated.