Hi Luis,
It may be a little late but I found myself in the same situation you were in just two days ago. After a lot of searching and learning how WordPress have implemented their PHP/CSS I came to the following solution.
Before I go on I need to say that this is likely not the only solution nor is it necessarily the best solution I know only that it works well for me on my site: techdistortion.com
The way codium-extend creates its custom header is by using the function add_custom_image_header() and it references two functions to do so: codium_extend_header_style() and codium_extend_admin_header_style(). These are all located in the functions.php file in the parent theme (codium-extend). Since you can’t redefine previously defined variables and since you can’t over-ride already defined functions neatly, it’s just easier to ignore those two functions created by codium-extend and simply create your own. He’s what I did:
<?php
// gets included in the site header
function td_header_style() {
?><style type="text/css">
div#header {
background: url("https://techdistortion.com/wp-content/themes/codium-extend-td/TD-1090x120.png") no-repeat;
height :120px;
-moz-border-radius:6px;
border-radius:6px;
}
<?php if ( 'blank' == get_header_textcolor() ) { ?>
h1.blogtitle,.description { display: none; }
<?php } else { ?>
h1.blogtitle a,.description { color:#<?php header_textcolor() ?>; }
<?php
} ?>
</style><?php
}
// gets included in the admin header
function td_admin_header_style() {
?><style type="text/css">
#headimg {
width:1090px;
height:120px;
}
</style><?php
}
?>
After this we’ve now setup the two functions how we want them and it’s time to remove the existing image header for which WordPress provide a function appropriately called remove_custom_image_header(). In order to execute this and our two new functions we need to wrap them in an action that takes place after the theme has finished its setup (if we don’t we’ll be removing an image header that hadn’t been created yet = this is bad) as follows:
<?php
add_action( 'after_setup_theme','remove_image_header', 100 );
function remove_image_header() {
remove_custom_image_header();
add_custom_image_header('td_header_style', 'td_admin_header_style');
}
?>
Of course you can name your two new functions whatever you like but I prefixed mine with “td” after my site.
All of this is all well and sedentary but the problem is that as of WordPress v3.4 (not released yet but will be soon) the add_customer_image_header is going to be deprecated. It’s advisable then to look into add_theme_support (‘custom header’); after that point. I’m assuming there will be an update to codium-extend to support add_theme_support at that time.
