<div class="sp-portfolio-thumb">
    <a href="<?php echo $item->link; ?>"><img src="<?php echo $item->image; ?>" alt="<?php echo $item->title; ?>" /></a>
    <div class="sp-portfolio-overlay">
        <div>
            <!--<a class="sp-portfolio-preview" rel="lightbox" title="<?php echo $item->title; ?>" href="<?php echo $item->image_full; ?>"><?php echo JText::_('PREVIEW'); ?></a>-->
            <?php if($show_readmore){ ?>
                <a class="sp-portfolio-link" href="<?php echo $item->urls->urla; ?>"><?php echo JText::_('MORE_DETAILS'); ?></a>
            <?php } ?>
        </div>
    </div>
</div>

<?php if ($item->image){ ?>
    <a href="<?php echo $item->link; ?>"><img src="<?php echo $item->image; ?>" alt="<?php echo $item->title; ?>" /></a>
<?php else ?>
    <img class="test" src="images/placeholder.jpg">
<?php } ?>

<?php if ($item->image) { ?>
...
    <?php } else { ?>
...
<?php } ?>

<?php if ($item->image) : ?>
...
    <?php else : ?>
...
<?php endif; ?>

$image = $item->image ? $item->image : 'images/placeholder.jpg';

<a href="<?php echo $item->link; ?>"><img src="<?php echo $image; ?>" alt="<?php echo $item->title; ?>" /></a>