[Mooff]

Neither the fallback image nor an error? That's really strange.
Please link me to your test site - if that's not possible please include a var_dump here:

old:

    //Randomize Array
    //shuffle($featured_articles);

new:

    //Randomize Array
    //shuffle($featured_articles);
var_dump($featured_articles);

given you still have ob_start(); and ob_end_clean(); commented out you should see a lot of debug information.