Option tree plugin

Hi, I am facing a problem with Option tree plugin. I want to create dynamic logo uploader. I used option tree plugin. Logo is uploaded successfully. But when it is retrieved nothing show on image section. Its only show an image sign. When I checked it via inspect element on browser its show two image source. Thats why it can not be retrieved.
I attached here all code which I used.

Function.php:

add_filter('ot_show_pages','__return_false');
add_filter('ot_show_new_layout','__return_false');
add_filter('ot_theme_mode','__return_true');
include_once('option-tree/ot-loader.php');
include_once('includes/theme-options.php');

theme-options.php:
<?php

add_action( 'admin_init', 'custom_theme_options', 1 );

function custom_theme_options() {

  $saved_settings = get_option( 'option_tree_settings', array() );

  $custom_settings = array(
    'sections'        => array(
      array(
        'id'          => 'general',
        'title'       => 'Site Settings'

    ),
	 array(
        'id'          => 'logo',
        'title'       => 'Logo Upload'
      )
    ),
    'settings'        => array(
      array(
        'id'          => 'logo_uploder',
        'label'       => 'Upload Your Logo',
        'desc'        => 'Upload your logo here only image file',
        'type'        => 'upload',
        'section'     => 'general'
      )
	 )
);

  if ( $saved_settings !== $custom_settings ) {
    update_option( 'option_tree_settings', $custom_settings );
  }

}
 ?>

then where i want to show:
<div class="fix-header">
<?php if( function_exists('get_option_tree')): if (get_option_tree('logo_uploder')): ?>
<a>"><img src="<?php echo get_option_tree('logo_uploder', '','true'); ?>"/></a>
<?php else: ?>
<a>"><img src="<?php echo get_template_directory_uri(); ?>/img/logo.png"/></a>
<?php endif; endif;?>
</div>

Please help me to fix it.