When you say the image inside the post do you mean the fullsize image that displays when your post is part of a portfolio? If this is the case and if you want the alt text to be the title of the post then open up /wp-content/themes/infocus/lib/includes/template-portfolio-single.php and on line 174 you should see this,
<span class="rm_portfolio_img noscript"><img title="portfolio1" src="<?php echo $portfolio_full; ?>" alt="" /></span>
Go ahead and change it like this,
<span class="rm_portfolio_img noscript"><img title="portfolio1" src="<?php echo $portfolio_full; ?>" alt="<?php the_title(); ?>" /></span>
Let us know if that is what you were wanting ASchoene.