getMainSiteURL [line 219]
Returns the URL of the main website as set by the "Website URL" option on the gallery options tab.

string getMainSiteURL( )

This is what I have in "Website URL" in gallery options:
http://www.panopixel.org/

I have this in index.php:
" title="Panopixel strona główna">

It returns this when I run it:

Why ""?

getmainSiteURL() is used to provide a link from your album to your "main" Web pages. It really has nothing to do with your image links.

I really don't understand the second part of your question. It looks as if what "it" returns is exactly what you put in index.php. Why would you expect it to be different?