Link front-page full-size images to their post url

There is no easy way to do this as your photo’s are already inserted into the posts. Have you thought about using post thumbnails

Or add a filter to the post content that alters the link address. Put this in your theme’s functions.php

add_filter('the_content', 'link_images_to_post');

function link_images_to_post($text){

	$upload_dir = wp_upload_dir();
	$upload_url = preg_quote($upload_dir['baseurl'], '/');

	global $post;
	if(empty($post->ID))
		return $text;

	// here starts the regex craziness!!
	if(preg_match('/<a(.*?)href="'.$upload_url.'(.*?)"(.*?)><img(.*?)src="'.$upload_url.'(.*?)"(.*?)><\/a>/', $text)){
		//there is a linked image attachement in the post_content

		$patterns = array(
		  '/<a(.*?)href="'.$upload_url.'(.*?)"(.*?)><img(.*?)src="'.$upload_url.'(.*?)"(.*?)><\/a>/'
		);

		$replacements = array(
		  '<a\1href="' . get_permalink($post->ID) . '"\3><img\4src="'.$upload_dir['baseurl'].'\5"\6></a>'
		);

		$text = preg_replace($patterns,$replacements,$text);
	}

	return $text;
}

Images will be linked to the post on the front end of your site. Only images that are linked to the file url will be altered to link to the post.

thanks for the reply..did not manage to make it work so far (string errors, brakes the site when c/p the above code) but it is a start…

I also found the following code

/**
 * Add post permalink to image post format
 */
function tab13_image_permalink($content){

	$format = get_post_format();
	$searchfor = '/(<img[^>]*\/>)/';
	$replacewith = '<a href="'.get_permalink().'">$1</a>';

	if (is_single() === FALSE AND $format == 'image'){
		$content = preg_replace($searchfor, $replacewith, $content, 1);
	}
	return $content;
}
add_filter('the_content', 'tab13_image_permalink');

this function is said to make the images on homepage to link to the post url, but so far also it is not working for me.. not even for the default theme.. well, in the end it will work, somehow, although i am not a php literate ??