WordPress retrieving wrong featured images

I’m working on a WordPress site which has 2 blocks with post teasers from 2 different categories. One block (cat = 8) displays well, but the other one displays incorrect featured images.

Here is the code of the page containing the 2 blocks. I have 2 more separate pagina for displaying the posts but the problem is the same there.

<div style="margin: 0; width: auto;">
                <h4 style="border-bottom: 1px solid #444;">Nieuws</h4>
                <span class="more-news">
                    <a href="nieuws">meer nieuwsberichten</a>
                </span>
                <?php $the_query = new WP_Query( array('showposts' => '2', 'cat' => '9') ); ?>
                <?php while ($the_query -> have_posts()) : ?>
                    <div class="unit-100 group teaser">
                        <?php if(has_post_thumbnail()){
                            $id = $the_query->post->ID;
                            echo get_the_post_thumbnail($id,array(100,100));
                            $the_query -> the_post(); ?>
                            <a href="<?php the_permalink() ?>"><?php the_title(); ?></a>
                            <?php the_excerpt(__('(lees meer…)'));
                        } else { 
                            $the_query -> the_post(); ?>
                            <a href="<?php the_permalink() ?>"><?php the_title(); ?></a>
                            <?php the_excerpt(__('(lees meer…)'));
                        } ?>    
                    </div>
                <?php endwhile; 
                wp_reset_postdata();?>
            </div>
                </div>
            <div class="unit-40">
            <div class="donate">
                <h4 style="border-bottom: 1px solid #444;">Doneer nu!</h4><?php echo do_shortcode('[IDEAL fip_referentie="The Blue Goat Donatie"]'); ?>
                </div>
            <div class="stories">
                <h4 style="border-bottom: 1px solid #444;">Bijzondere verhalen uit Oeganda</h4>
                <p><?php echo do_shortcode('[contentblock id=bijzondere-verhalen]'); ?></p>

                <?php $the_query2 = new WP_Query( array('showposts' => '1', 'cat' => '8') ); ?>
                <div class="">
                        <?php while ($the_query2 -> have_posts()) :
                        if(has_post_thumbnail()){
                            the_post_thumbnail(array(350,350));
                            $the_query2 -> the_post(); ?>                           
                            <span class="story-title"><a href="<?php the_permalink() ?>"><?php 
the_title(); ?></a></span>
                        <?php } else {
                            $the_query2 -> the_post(); ?>
                            <a href="<?php the_permalink() ?>">Lees meer....</a>
                        <?php }
                    endwhile;
                    wp_reset_postdata(); ?>
                    </div>
                </div>