child-theme functions.php to edit header/login logo

Here is what I tried:

function custom_logo() {

echo ‘<style type=”text/css”>

#header-logo { background-image:url(https://xyz.org/wp-content/uploads/2013/logo.png)!important; }

</style>’;

}

add_action(‘admin_head’, ‘custom_logo’:wink:;

function custom_login_logo() {

echo ‘<style type=”text/css”>

h1 a { background-image:url(https://xyz.org/wp-content/uploads/2013/logo.png)!important; }

</style>’;

}

add_action(‘login_head’, ‘custom_login_logo’:wink:;

But I’m getting the following errors:

Warning: Cannot modify header information – headers already sent by (/wp-content/plugins/woocommerce/classes/class-wc-session-handler.php and /wp-includes/pluggable.php(pluggable.php error on multiple lines)).

Any suggestions?

EDIT:

So it’s caused by output coming before those header mods. Output Buffering workaround doesn’t seem to be working. Re-coding /wp-includes/pluggable.php or restructuring the application flow is beyond me at this point. Anyone know other workarounds I can try?