How to add testimonials with an image?

Make a new category called Testimonials then, in your theme folder add a new file called testimonials.php.

Add this in the newly created file:

<div id="testimonials">
    <?php $args = array('caller_get_posts' => 1, 'post_type' => 'testimonials', 'post_status' => 'publish', 'posts_per_page' => 5);
    query_posts($args);
    if (have_posts()) : while (have_posts()) : the_post(); 
    $image = get_post_meta($post->ID, 'testimonial-image', true);
    ?>

        <div class="testimonail">
            <img src="https://wordpress.stackexchange.com/questions/10032/<?php echo $image; ?>" width="" height="" alt="<?php the_title(); ?>" />
            <h2><?php the_title(); ?></h2>
            <?php the_content(); ?>
        </div>

    <?php endwhile; else : endif; ?>
</div>

Then add where do you want the testimonials to show. Example footer.php

Now you can add testimonials by simply adding a new post and fill it under the Testimonials category. As for the image, make a new custom field called testimonial-image and for the value add the path to the image (ex: http://example.com/image.png).

And you are good to go.