Thumbnail not work..

Just i have problem with thumbnail…
i use front-page.php thumbnail not work only index.php works so here code check it out which one wrong… pls, help me..

For function.php

<?php
//****** Code For Thumbnail *******
add_theme_support('post-thumbnails');
add_image_size('index-post-thumbnail', 170, 100, true);
set_post_thumbnail_size(100, 75, true);
set_post_thumbnail_size(100, 75);
 ?>

For any template

<!---Open Thumbnail WP--->
<?php if(have_posts()) : ?><?php while(have_posts()) : the_post(); ?>
<a href=<?php the_permalink(); ?> />
<?php the_post_thumbnail('index-post-thumbnail'); ?>
<?php the_title(); ?></a>
<?php endwhile; ?><?php endif; ?>
<!---Close Thumbnail WP--->