Hello, I am a new convert to Omeka and a very novice developer. I've found lots of posts of people asking for help configuring a Javascript or jQuery slideshow/gallery, but would really value some instructions on how to configure a freely available one such as Spacegallery or Showcase for using in Omeka. I've been customising the Rhythm theme and it now does everything I'd like it to except having an eyecatching slideshow on the homepage.
Each of the gallery scripts you link to appears to provide some documentation and implementation code...have you tried following their suggestions?
Just wanted to say I overcame my struggles by using the Deco theme and customising lots of elements. It's a superb theme, if there's anyone comes across this post who, like me, doesn't have all the technical skills required to implement a slideshow and lightbox but wants to use them with Omeka, I'd really recommend this theme as a great way to do it.