We do not support slideshow navigation in media gallery. I can't recall why, but if that's the specific thing you're after I recommend posting about that specifically in a new thread in the Media Gallery suggestions forum.
Wouldn't it simply be a matter of switching it on in the options? I'll certainly add a suggestion but comman sense says one should be the same as the other and whats a media gallery without slideshow.
Regardless, whether it would take 30 seconds to enable it or several hours of development time, it would need to be posted as a suggestion for consideration in the future.
No I cannot do that because there isn't a config file. It is something in the code itself and that's not something we would be able to provide support for.