To run any type of file in WordPress, it is necessary to give the address of the location.
How To
>> Open Theme folder and file.
>> Store any one file to locate in custom theme.
example – customtheme > image > logo.jpg
>> thene add this code where you locate stored file.
<img src="<?php echo get_template_directory_uri(); ?>/image/logo.jpg" width="20px" height="20px" alt="" />
>> then save Theme.