Define settings in template config page

I can define new settings for my template and save/restore them in admin section of themplate, but how i can use those settings in front-end? is it possible to do this without using ocmod or touching core files?

Could you please provide an example?

currently i am working on new theme, in this theme user will be able to select header image, so i need create new setting for header image in setting section of template module, i did that but now i want to retrieve that path/url of image in header.tpl.

i did that by using ocmod and virtually editing header.php file. my question is that how i could do this without using ocmod?

Perhaps to investigate the use of additional layout positions in the header to embed your components so that the user can then choose to embed them using Layouts? I think there is a lot of Q&A around the forums if you search for it.