Show different size featured images (the_post_thumbnail) for 1st, 2nd and 3rd posts?

Question

I file all the galleries on my blog under the 'gallery' tag. I use the following code (via) to display the latest 7 gallery posts after the 8th latest post on home page:

<!-- Featured post galleries after 8th post -->
<?php
   $homegallery++;
   if ($homegallery == 8){
?>

<!-- Display Gallery Posts -->
<div id="gallery-posts">
<?php
    $count = 0;
    $some_featured_posts = new WP_Query(array('category_name' => 'apps', 'posts_per_page' => 5));
    while ($some_featured_posts->have_posts()): 
        $some_featured_posts->the_post();
        $count++;
?>

<?php the_post_thumbnail( 'thumbnail' ); ?>

<?php
    endwhile;
    wp_reset_postdata();
?>
</div><!-- Display Gallery Posts END -->

<?php
   };
?><!-- Featured post galleries END -->

As you can see, I use a thumbnail to represent each post <?php the_post_thumbnail( 'thumbnail' ); ?>, may look weird, but that's how I do it. But I would like to show the thumbnails of first two posts in one size (large), the third one in one size (medium) and the rest in another size (thumbnail).

How do I do this?

---

In case it helps, I've got this far with some help:

<?php
    $loop_first = 1;
    if ( ! isset ( $loop_first ) ) {

    // set featured image size for first post
    the_post_thumbnail( 'medium' );
    } else {

    // set featured image size for other posts
    the_post_thumbnail( 'thumbnail' );
    }
?>

The above code (I believe) allows me to show a different size image for the first post, and different size thumbnails for the rest of the posts.

Answer 1

Just use the $count variable that you are incrementing:

<?php
    $count = 0;
    $some_featured_posts = new WP_Query(array('category_name' => 'apps', 'posts_per_page' => 5));
    while ($some_featured_posts->have_posts()): 
        $some_featured_posts->the_post();
        $count++;

        if( $count <= 2 )
          the_post_thumbnail( 'large' ); 

        elseif( 3 == $count )
          the_post_thumbnail( 'medium' ); 

        else
          the_post_thumbnail( 'thumbnail' ); 


    endwhile;
    wp_reset_postdata();
?>

Answer 2

yes thats v great idea but the problem is that it repeats all the images for every condition i mean that it display all the images while we have a condition here like...

<?php $count = 0;
    $some_featured_posts = new WP_Query(array('category_name' => 'latest-products', 'posts_per_page' => 6));
    while ($some_featured_posts->have_posts()): 
        $some_featured_posts->the_post();
        $count++;

    if( $count == 0 )?>
    <div class="first-row" style="float:left">
    <div class="first-img"><?php the_post_thumbnail( array(200,400) ); ?></div>
   <?php  if  ( $count == 1 )  ?>
    <div class="second-img"><?php the_post_thumbnail( array(100,100) ); ?></div>

    </div>
     <?php if( 2 == $count ) ?>
      <div class="second-row" style="float:left">
    <div class="secondrow-first-img"><?php the_post_thumbnail( array(200,300) ); ?></div>
          <?php if( 3 == $count ) ?>
    <div class="secondrow-second-img"><?php the_post_thumbnail( array(100,75) ); ?></div>
     <?php if( 4 == $count ) ?>
    <div class="secondrow-third-img"><?php the_post_thumbnail( array(400,300) ); ?></div>

    </div>
     <?php if( 5 == $count ) ?>
      <div class="third-row" style="float:left">
    <div class="thirdrow-first-img"><?php the_post_thumbnail( array(200,500) ); ?></div>


    </div>