Responsive for Image elements do not have explicit width and height

[jwugit]

Anyone know how to handle responsive ?

i can add width + height to my to resolve the lighthouse error.
but im using picture element with sources that have different aspect ratios for desktop versus mobile

for example

<picture>
<source   desktop media...some image with aspect ration 500:200 />
<source   mobile media...some image with aspect ration 300:600 />
<img width="???" height="???" />
</picture>

what would width + height for image be, if the aspect ration needs to be different ?

Thanks