A WordPress widget that generates a JPG of the first page of the first PDF it finds attached to the page it's assigned to.

individual-document.php

<?php 

function load_pmg_single_doc() {
	register_widget('PMG_Single_Doc'); 
}
add_action('widgets_init', 'load_pmg_single_doc');

class PMG_Single_Doc extends WP_Widget {

	function PMG_Single_Doc() {
		$widget_ops = array('classname' => 'widget_text', 'description' => __('A widget that displays download links to a document of your choosing.'));
		$control_ops = array('width' => 400, 'height' => 350);
		$this->WP_Widget('PMG_Single_Doc', 'Single Document Widget', $widget_ops, $control_ops );
	}

	function widget( $args, $instance ) {
		extract($args);
		$title = apply_filters( 'widget_title', empty( $instance['title'] ) ? '' : $instance['title'], $instance, $this->id_base );
		$url = apply_filters( 'widget_url', empty( $instance['url'] ) ? '' : $instance['url'], $instance );
		$desc = apply_filters( 'widget_text', empty( $instance['desc'] ) ? '' : $instance['desc'], $instance );
		$alldocslink = apply_filters( 'widget_text', empty( $instance['alldocslink'] ) ? '' : $instance['alldocslink'], $instance );
		$alldocstext = apply_filters( 'widget_text', empty( $instance['alldocstext'] ) ? '' : $instance['alldocstext'], $instance );
		
		$before_widget = preg_replace('/class="(.*?)"/i', 'class="$1 downloadsWidget"', $before_widget);
		
		echo $before_widget;
		
		if ( !empty( $title ) ) { echo $before_title . $title . $after_title; } ?>
			<?php
		
				if ( $url ) {		
					$pdf = $url;
					$info = pathinfo($pdf);
					$filename =  basename($pdf,'.'.$info['extension']);
					
					$uploads = wp_upload_dir();
					$file_path = str_replace( $uploads['baseurl'], $uploads['basedir'], $url );
					$dest_path = str_replace( '.pdf', '.jpg', $file_path );
					$dest_url = str_replace( '.pdf', '.jpg', $pdf );
						
					if ( !file_exists( $dest_path ) ) {
						exec("convert \"{$file_path}[0]\" -colorspace RGB -geometry 60 $dest_path");
					}; ?>
					<div class="entry">
						<div class="widgetImg">
							<p><a href="<?php echo $url; ?>" title="<?php echo $filename; ?>"><?php echo "<img src='".$dest_url."' alt='".$filename."' class='blueBorder' />"; ?></a></p>
						</div>
						
						<div class="widgetText">
							<?php echo wpautop( $desc ); ?>
							
							<p><a class="downloadLink" href="<?php echo $url; ?>" title="<?php echo $filename; ?>">Download</a></p>
							<?php if ( $alldocslink ) { ?>
							<p style="font-size:12px;"><a href="<?php echo $alldocslink; ?>" title="<?php if ( $alldocstext ) { echo $alldocstext; } else { ?>More Brochures<?php } ?>"><?php if ( $alldocstext ) { echo $alldocstext; } else { ?>More Brochures<?php } ?></a></p><?php } ?>
						</div>
					</div>
					<?php }
			?>
		<?php
		echo $after_widget;
	}

	function update( $new_instance, $old_instance ) {
		$instance = $old_instance;
		$instance['title'] = strip_tags($new_instance['title']);
		$instance['url'] = strip_tags($new_instance['url']);
		$instance['alldocslink'] = strip_tags($new_instance['alldocslink']);
		$instance['alldocstext'] = strip_tags($new_instance['alldocstext']);
		if ( current_user_can('unfiltered_html') )
			$instance['desc'] =  $new_instance['desc'];
		else
			$instance['desc'] = stripslashes( wp_filter_post_kses( addslashes($new_instance['desc']) ) ); // wp_filter_post_kses() expects slashed
		
		$instance['filter'] = isset($new_instance['filter']);
		return $instance;
	}

	function form( $instance ) {
		$instance = wp_parse_args( (array) $instance, array( 'title' => '', 'desc' => '', 'url' => '', 'alldocslink' => '', 'alldocstext' => ''  ) );
		$title = strip_tags($instance['title']);
		$url = strip_tags($instance['url']);
		$alldocslink = strip_tags($instance['alldocslink']);
		$alldocstext = strip_tags($instance['alldocstext']);
		$desc = esc_textarea($instance['desc']);
?>
		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr($title); ?>" /></p>
		
		<p><label for="<?php echo $this->get_field_id('url'); ?>"><?php _e('URL of PDF attachment <em>(must be PDF)</em>:'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('url'); ?>" name="<?php echo $this->get_field_name('url'); ?>" type="text" value="<?php echo esc_attr($url); ?>" /></p>
		
		<p><label for="<?php echo $this->get_field_id('desc'); ?>"><?php _e('Description:'); ?></label>
		<textarea class="widefat" id="<?php echo $this->get_field_id('desc'); ?>" name="<?php echo $this->get_field_name('desc'); ?>"><?php echo $desc; ?></textarea></p>
		
		<p><label for="<?php echo $this->get_field_id('alldocslink'); ?>"><?php _e('Link to all documents (optional):'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('alldocslink'); ?>" name="<?php echo $this->get_field_name('alldocslink'); ?>" type="text" value="<?php echo esc_attr($alldocslink); ?>" /></p>
		
		<p><label for="<?php echo $this->get_field_id('alldocstext'); ?>"><?php _e('Text for link to all docs (optional):'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('alldocstext'); ?>" name="<?php echo $this->get_field_name('alldocstext'); ?>" type="text" value="<?php echo esc_attr($alldocstext); ?>" /></p>
<?php
	}
}
?>