You need to edit _item_block.inc.php file. Add the following code

// Default params:
$params = array_merge( array(
		'<div class="post-content clear-block">',
		'feature_block'		=> false,
		'content_mode'		=> 'auto',		// 'auto' will auto select depending on $disp-detail
		'item_class'		=> 'bPost',
		'image_size'		=> 'fit-400x320',
		'before_more_link'	=> '<span class="more-link">',
		'after_more_link'	=> '</span>',
	), $params );

// Link images to the artile
$params['image_link_to'] = 'single';
$params['excerpt_image_link_to'] = 'single';

Alternatively you can link images to the article in post list mode (homepage) and to the original images in single post mode (when you are already on the article page)

if( $disp == 'posts' )
{
	$params['image_link_to'] =  'single';
	$params['excerpt_image_link_to'] = 'single';
}

Tat appears to kill my page, displays no posts after changing :(

tried adding like above and also tried...

// Default params:
$params = array_merge( array(
		'<div class="post-content clear-block">',
		'feature_block'		=> false,
		'content_mode'		=> 'auto',		// 'auto' will auto select depending on $disp-detail
		'item_class'		=> 'bPost',
		'image_size'		=> 'fit-400x320',
                'image_link_to'         => 'single'; 
                'excerpt_image_link_to' => 'single'; 
		'before_more_link'	=> '<span class="more-link">',
		'after_more_link'	=> '</span>',
	), $params );

breaks page - no posts just blank after really long load time

That was my mistake, I edited the code. Please try again

Cheers working well :)