Unless otherwise indicated, the code snippets you see below should be placed into your theme’s functions.php file.
Here is the code needed to remove the post format image on your site:
<?php //* Do NOT include the opening php tag shown above. Copy the code shown below. //* Remove the post format image (requires HTML5 theme support) remove_action( 'genesis_entry_header', 'genesis_do_post_format_image', 4 );