Fast Lane!

Seems simply upgrading MyISAM tables (notably core_search_index) fixed the issue. Crazy.  Not sure I can fully explain this -- but it worked.  Seems like more than row vs. table locking at work here.

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.