There's some new code in the six theme header.tpl in WHMCS 7.2:
{if $assetLogoPath}
<a href="{$WEB_ROOT}/index.php" class="logo"><img src="{$assetLogoPath}" alt="{$companyname}"></a>
{else}
<a href="{$WEB_ROOT}/index.php" class="logo logo-text">{$companyname}</a>
{/if}
Can anyone advise where $assetLogoPath is defined? I can't seem to find a way to set this / upload a logo in WHMCS admin. Specifying the logo option in WHMCS admin does not seem to change this, it only affects the logo used in email messages.