Image height and width attributes not rendered when using Glass Mapper

Question

Glass Mapper (version 5.8.177) doesn't seem to output height and width attributes in preview or live mode

It renders

<img src="/media/testing/images/hero/trust.svg?h=47&amp;w=100&amp;la=en&amp;hash=D49AEE9828CBDB902F3E2503FFFCEC64" alt="Trust rating">

Rather

<img src="/media/testing/images/hero/trust.svg?h=47&amp;w=100&amp;la=en&amp;hash=D49AEE9828CBDB902F3E2503FFFCEC64" height="47" width="100" alt="Trust rating">

I've been asked as to why height/width attributes are not used as it is a general SEO recommendation to avoid layout shifts etc,

Is there a reason why Glass Mapper doesn't add these attributes in preview/live mode?