Fast Lane!'s post in 4.6.6 Email Header Logo HUGE was marked as the answer
September 16, 2021
The fix in the email template seems easy enough... see below. thoughts?
Email template: Email Wrapper
Before:
<a href='{setting="base_url"}' style='text-decoration: none; color: #262e33; border: 0;'>
{{$imgDims=NULL;}}
{{if \IPS\Settings::i()->email_logo}}
{{try { $imgDims = \IPS\File::get( 'core_Theme', \IPS\Settings::i()->email_logo )->getImageDimensions(); } catch( \Exception $e ) {} }}
{{endif}}
{{if $imgDims}}
<img src='{file="\IPS\Settings::i()->email_logo" extension="core_Theme"}' alt="{setting="board_name"}" width='{$imgDims[0]}' height='{$imgDims[1]}' />
{{else}}
{setting="board_name"}
{{endif}}
</a>
After:
<a href='{setting="base_url"}' style='text-decoration: none; color: #262e33; border: 0;'>
{{$imgDims=NULL;}}
{{if \IPS\Settings::i()->email_logo}}
{{try { $imgDims = \IPS\File::get( 'core_Theme', \IPS\Settings::i()->email_logo )->getImageDimensions(); } catch( \Exception $e ) {} }}
{{endif}}
{{if $imgDims}}
<img src='{file="\IPS\Settings::i()->email_logo" extension="core_Theme"}' alt="{setting="board_name"}" width='100%' />
{{else}}
{setting="board_name"}
{{endif}}
</a>
The key change being to set width to 100% (and delete the hard coded height and width). Height will then auto calculate.