Adding schema to text content in the loop, how?

Just add them to echo

<?php if ( has_post_thumbnail() ) {
    the_post_thumbnail(
        'full',
        array(
            'class'=>'post_thumbnail_common',
            'alt' => get_the_title() ,
            'title' => get_the_title(),
            'itemprop'=>'image'
        )
    );
    echo '<div itemscope itemtype="http://schema.org/BlogPosting">'.contentnoimg(41).'</div>';
} else { 
    echo content(41);
} ?>