plugin-file.php

<?php
/*
Plugin Name: Colornews Image Upload
Plugin URI: http://bobl.com.bd/
Description: It is a simple plugin that adds a widget to your favourite sidebar to upload a single image and show it in sidebar location with custom url whatever you want
Version: 1.0
Author: BOBL
Author URI: http://bobl.com.bd/
*/
?>
<?php
class colornewsImageUploader extends WP_Widget
{
	
	/**
	* Widget construction
	*/
	function __construct()
	{
		$widget_ops = array('classname' => 'widget_image image-upload-widget', 'description' => __('Image, link'));
        $control_ops = array('width' => 278);
        parent::__construct('colornewsImageUploader', __('Fixed Advertise Image Upload', 'colornews'), $widget_ops, $control_ops);
	}
	
	public function widget( $args, $instance )
	{
		if (!isset($args['widget_id'])) {
          $args['widget_id'] = null;
        }
		
		extract($args);
		
		$title = apply_filters('widget_title', empty($instance['title']) ? '' : $instance['title'], $instance);
		$imageUri = empty($instance['image_uri']) ? '' : $instance['image_uri'];
		$url = empty($instance['url']) ? '' : $instance['url'];
		 
	}
	
	
	    /**
     * Run on widget update
     */
    function update( $new_instance, $old_instance ) {
        $instance = $old_instance;
		$instance['title'] = strip_tags($new_instance['title']);
		$instance['image_uri'] = strip_tags($new_instance['image_uri']);
		$instance['url'] = strip_tags($new_instance['url']);
      
        return $instance;
    }
  
    /**
     * Setup the widget admin form
     */
	public function form( $instance )
	{
		$instance = wp_parse_args( (array) $instance, array(
            'title' => '',
			'image_uri' => '',
			'url' => '',
        ));
        $title = $instance['title'];
        $imageUri = $instance['image_uri'];
		$url = $instance['url'];
		?>
		<p>
		  <label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title', 'colornews'); ?>:</label><br />
		  <input type="text" name="<?php echo $this->get_field_name('title'); ?>" id="<?php echo $this->get_field_id('title'); ?>" value="<?php echo $title ?>" class="widefat" />
		</p>
		<p>
		  <label for="<?php echo $this->get_field_id('image_uri'); ?>"><?php _e('Image', 'colornews'); ?>:</label><br />
		  <input type="text" class="img" name="<?php echo $this->get_field_name('image_uri'); ?>" id="<?php echo $this->get_field_id('image_uri'); ?>" value="<?php echo $imageUri; ?>" />
		  <input type="button" class="select-img" value="Select Image" />
		</p>
		<p>
		  <label for="<?php echo $this->get_field_id('url'); ?>"><?php _e('Link', 'colornews'); ?>:</label><br />
		  <input type="text" name="<?php echo $this->get_field_name('url'); ?>" id="<?php echo $this->get_field_id('url'); ?>" value="<?php echo $url; ?>" class="widefat" />
		</p>
		<?php
	  }
} 

// queue up the necessary js
function imgupl_enqueue()
{
  wp_enqueue_style('thickbox');
  wp_enqueue_script('media-upload');
  wp_enqueue_script('thickbox');
  wp_enqueue_script('hrw', plugin_dir_url( __FILE__ ).'/js/script.js', null, null, true);
}
add_action('admin_enqueue_scripts', 'imgupl_enqueue');

/**
 * Register the widget
 */
function colornews_Image_Upload_Widget_init() {
    register_widget('colornewsImageUploader');
}
add_action('widgets_init', 'colornews_Image_Upload_Widget_init');

upload-script.js

var image_field;
jQuery(function($){
  $(document).on('click', 'input.select-img', function(evt){
    image_field = $(this).siblings('.img');
    tb_show('', 'media-upload.php?type=image&TB_iframe=true');
    return false;
  });
  window.send_to_editor = function(html) {
    imgurl = $('img', html).attr('src');
    image_field.val(imgurl);
    tb_remove();
  }
});