We have changed this image with custom PHP code added to the functions.php file in the child theme
function woodmart_site_get_avatar($avatar, $id_or_email, $size, $default, $alt){
global $wp_query;
if ( is_object( $id_or_email ) && $id_or_email->user_id == 1 ){
$avatar = '<img class="avatar avatar-32 photo" src="IMAGEURL.jpg" height='.$size.' width='.$size.' />';
} elseif ( !is_object( $id_or_email ) && $id_or_email == 1 ) {
$avatar = '<img class="avatar avatar-32 photo" src="IMAGEURL.jpg" height='.$size.' width='.$size.' />';
}
return $avatar;
}
add_filter('get_avatar', 'woodmart_site_get_avatar', 10, 5);