Document get_header_image() return value better

[rulatir]

The documentation for get_header_image() here:

​http://codex.wordpress.org/Function_Reference/get_header_image

says that the function returns "header image path". If the word path is to be understood as it is apparently understood throughout the Codex, then this documentation is incorrect, because the function actually returns a url, not a path.

I realized only now that I was getting a full HTTP URL with scheme, host and path from this function. I was happily passing it to getimagesize() and it just happened to work because allow_url_fopen was on. Then the customer moved the site to another hosting account (with the same provider but different setup) and it stopped working.

[SergeyBiryukov]

I've corrected the inaccurate description. The Codex is a wiki, anyone with a WordPress.org account can make changes there.