Hyperlinking images on posts to permalink

If they are featured images or post Thumbnails U can add this code in functions.php to link them

add_filter( 'post_thumbnail_html', 'my_post_image_html', 10, 3 );

function my_post_image_html( $html, $post_id, $post_image_id ) {

$html="<a href="" . get_permalink( $post_id ) . '" title="' . esc_attr(   get_post_field( 'post_title', $post_id ) ) . '">' . $html . '</a>';
 return $html;

}

If U need to add theme support then refer to this link

http://codex.wordpress.org/Function_Reference/the_post_thumbnail

Or else if U don’t prefer to add this code just find files like

Loop.php , content.php,-main.php,index.php, home.php

And then just press F3 in this files and search for

 the_post_thumbnail

And Permalink that code

And if U don’t find that then it may possible that ur themeay using tbe_content for it