[Plugin: Simple Portfolio] Full Size Image instead of Thumbnails

I am new to wordpress, but stumbling through this code.
I am using the simple-portfolio sample theme to structure this plug-in within my own theme, but I need to display the full-size photos in the single-portfolio.php. Somewhere, the image class is being set to thumbnail size, but I can’t figure out where.

I don’t know if this will help…but this is my file so far

<div id="container">

				<?php get_template_part( 'loop', 'index' ); ?>

				<div id="workcontent">
					<div id="port-info">
					<div class="title"><?php the_title(); ?></div>
					<?php foreach (simple_portfolio_info() as $key=>$info_item): $key = explode('_', $key); array_shift($key); $key = ucfirst(implode(' ', $key)); ?>
							<div class="box">
								<span><?php echo $key; ?></span>
								<?php echo trim($info_item) == '' ? '...' : $info_item; ?>
							</div>
					<?php endforeach; ?>
				</div>

				<div id="gallery">
					<?php foreach (simple_portfolio_media() as $media_item): ?>
					<?php
						switch ($media_item['type']):
							case 'image':
								$src = wp_get_attachment_image_src($media_item['value'], 'full');
								echo "<a href=\"$src[0]\">" . wp_get_attachment_image($media_item['value']) . "</a>";
								break;
							case 'youtube':
								echo "<p>";
								echo "<object width=\"480\" height=\"385\">";
								echo "	<param name=\"movie\" value=\"https://www.youtube.com/" . $media_item['value'] . "&hl=en_US&fs=1\"/>";
								echo "	<param name=\"allowFullScreen\" value=\"true\"/>";
								echo "	<param name=\"allowscriptaccess\" value=\"always\"/>";
								echo "	<embed src=\"https://www.youtube.com/v/" . $media_item['value'] . "&hl=en_US&fs=1\" type=\"application/x-shockwave-flash\" allowscriptaccess=\"always\" allowfullscreen=\"true\" width=\"480\" height=\"385\"/>";
								echo "</object>";
								echo "</p>";
								break;
							case 'snippet':
								echo $media_item['value'];
								break;
						endswitch;
					?>
					<?php endforeach; ?>
				</div>

	</div>

Thanks in advance for any advice!