<a href="images/portfolio/full/portfolio_3.png" class="fa fa-search mfp-image"></a>
<a href="<?php the_post_thumbnail( 'full', array( 'class' => 'fa fa-search mfp-image' )); ?>"></a>
question from:https://stackoverflow.com/questions/65651428/search-icon-is-not-displaying-correct-inside-the-a-href-php-the-post-thumbna