Image in Header.php file shows up on home page of a Wordpress site, but not on the other pages

I want to have a small image appear before my WordPress Site Name in the navbar.

This is the code I wrote into the header.php file to make the image appear.

<a class="navbar-brand" href="<?php echo home_url(); ?>">
  <img src="img/logo.png" width="25px" height="25px" style="top: -3px; position: relative;"/> 
  &nbsp; 
  <?php bloginfo('name'); ?>
</a>

I have placed the img folder, with the logo.png inside of it, in the root of my web hosting, in the wp-content, and the theme folder.

I hosted WordPress on my laptop to develop with WAMP Server, and it worked when I was working on it, but when I went to put it up on GoDaddy the error occurred.

It looks like the logo.png file cannot be found except when on the homepage of the site, which is the static home page.

I appreciate any help you guys have, and if there needs to be anymore information provided, I will be glad to oblige.