Widget that allows users to pull featured image and link for either a selected page, or the latest blog post. I wrote this for a custom homepage widget, but it might be useful for something else later -- especially the per-page functionality.

pageorblogwidget.php

<?php
// This is a widget for Homepage Widgets

// initializes the widget on WordPress Load
add_action('widgets_init', 'homepage_widget_init_widget');

// Should be called above from "add_action"
function homepage_widget_init_widget() {
	register_widget( 'HomepageWidget' );
}

// new class to extend WP_Widget function
class HomepageWidget extends WP_Widget {
	/** Widget setup.  */
	function HomepageWidget() {
		/* Widget settings. */
		$widget_ops = array(
			'classname' => 'homepage_widget',
			'description' => __('Homepage Widgets', 'homepage_widget') );

		/* Widget control settings. */
		$control_ops = array( 'width' => 300, 'height' => 350, 'id_base' => 'homepage_widget' );

		/* Create the widget. */
		$this->WP_Widget( 'homepage_widget', __('Homepage Widget', 'Options'), $widget_ops, $control_ops );
	}
	/**
	* How to display the widget on the screen. */
	function widget( $args, $instance ) {
		extract( $args );
		$title = apply_filters('widget_title', $instance['title'] );
		$selected = $instance['content_type'];
		$pages = $instance['pages'];
		$summary = $instance['summary'];
		echo $before_widget;
		?>
		<div class="widget-inner">
			<?php
			if ($selected == 'blog'):
				$query = new WP_Query(array(
					'post_type' => 'post',
					'posts_per_page' => 1
				));
			else :
				$query = new WP_Query(array(
					'p' => $pages,
					'post_type' => 'page',
					'posts_per_page' => 1
				));
			endif;
			if ($query->have_posts()) : while ($query->have_posts()) : $query-> the_post(); ?>
				<a href="<?php the_permalink(); ?>">
					<?php the_post_thumbnail(array(105,105), array('title' => $post->post_title)); ?>
				</a>
			<?php
			if ( $title )
			echo $before_title . $title . $after_title; ?>
			<p>
			<?php if ($selected == 'page'): ?>
				<?php echo $summary; ?>
			<?php else : ?>
				<?php the_title(); ?>
			<?php endif; ?>
			</p>
				<p><a class="btn btn-white" href="<?php the_permalink(); ?>">Read More</a></p>
			<?php endwhile; ?>
			<?php endif; ?>
		</div><!--end widget-inner -->
		<?php
		/* Before widget (defined by themes). */

		
		/* Display name from widget settings if one was input. */
		
		// Settings from the widget
		
		
		/* After widget (defined by themes). */
		echo $after_widget;
	}

	/**
	 * Update the widget settings.
	 */
	function update( $new_instance, $old_instance ) {
		$instance = $old_instance;

		/* Strip tags for title and name to remove HTML (important for text inputs). */
		$instance['title'] = strip_tags( $new_instance['title'] );
		$instance['content_type'] = $new_instance['content_type'];
		$instance['pages'] = $new_instance['pages'];		
		$instance['summary'] = $new_instance['summary'];
		return $instance;
	}
	
/**
 * Displays the widget settings controls on the widget panel.
 * Make use of the get_field_id() and get_field_name() function
 * when creating your form elements. This handles the confusing stuff.
*/
function form($instance) {
	$defaults = array( 
		'title' => __('Homepage Widgets', 'homepage_widget'),
		'content_type' => 'page'
	);
	$instance = wp_parse_args( (array) $instance, $defaults ); ?>
	<!-- Widget Title: Text Input -->
	<p>
		<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e('Title:', 'homepage_widget'); ?></label><br>
		<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" value="<?php echo $instance['title']; ?>">
	</p>
	<p>
		<label for="<?php echo $this->get_field_id( 'content_type' ); ?>">Select the type of content this widget will display</label>
		<select name="<?php echo $this->get_field_name( 'content_type' ); ?>" id="<?php echo $this->get_field_id( 'content_type' ); ?>">
			<option <?php if ($instance['content_type'] == 'blog') :?>selected <?php endif; ?> value="blog">First Blog Post</option>
			<option <?php if ($instance['content_type'] == 'page') :?>selected <?php endif; ?> value="page">Selected Page</option>
		</select>
	</p>
	<p class="pages_container">
		<select style="width: 80%;" id="<?php echo $this->get_field_id( 'pages' ); ?>" name="<?php echo $this->get_field_name( 'pages' ); ?>" id="pages">
			<?php $pages = get_posts('numberposts=-1&orderby=menu_order&order=ASC&post_type=page&post_status=publish');?>
			<option value="0">Select the page you'd like to use</option>
			<?php foreach ($pages as $page): ?>
				<option <?php if ($instance['pages'] == $page->ID): ?>selected <?php endif ?>value="<?php echo $page->ID; ?>"><?php echo $page->post_title; ?></option>
			<?php endforeach; ?>
		</select><br><br>
		<label for="<?php echo $this->get_field_id( 'summary' ); ?>"><?php _e('Summary Text:', 'homepage_widget'); ?></label><br>
		<input type="text" class="widefat" id="<?php echo $this->get_field_id( 'summary' ); ?>" name="<?php echo $this->get_field_name( 'summary' ); ?>" value="<?php echo $instance['summary']; ?>">
	</p>
	
	<?php
	}
} // END HomepageWidget