[@kachan64 Participant 11 years, 1 month ago]

	    if ( has_post_thumbnail($post->ID) )
	    	echo get_the_post_thumbnail($post->ID,'thumbnail',array('class' => 'alignleft forum-icon'));
	 }

This is the styling for the featured image.

bbp_theme_before_topic_title
This part of the code determents where should featured image goes. You will need to check your code.