Having admin on different host breaks attached images

Sometimes it’s nice to have admin on a different host (admin.mysite.com) then the actual site (www.mysite.com).

If admin.mysite.com is not publicly accessible, then images attached to posts on admin.mysite.com will not be accessible on www.mysite.com since the url to the attached image is absolute and contains the domain (admin.mysite.com).

Is there any way to fix this? The nicest way would be if the url to an attached media would be relative and not absolute.

you can configure the tinymce to use relative paths for images using the tiny_mce_before_init like this:

function tinymce_relative_path( $init ) {
 $init['relative_urls'] = true;
 $init['document_base_url'] = 'http://www.mysite.com';
 return $init;
}
add_filter('tiny_mce_before_init', 'tinymce_relative_path');