Can iPhoto slideshows be made functional again in Photos?
I just upgraded an 8GB Mac Mini from Mavericks to El Capitan. (Yep, I skipped Yosemite entirely.) No issues with the upgrade, everything went fine, and I like the new look.
In Mavericks, I used iPhoto to create a lot of slideshows from photo albums. The slideshows weren't terribly elaborate, but they contained resized images (to fit the 16:9 ratio of an HDTV at 1920 x 1080 pixels), as well as some transitions, varied lengths of image display and sometimes music. I've invested a lot of time into these, as there are about 30 slideshows in all, each with about 200 images.
Now, in Photos, under El Capitan, the slideshows appear, but all the stuff I added (or adjusted) is gone -- the frame-filling 16x9 crops are now just 4:3 with vertical black bars, transitions are gone, music is gone.
Is there a way to get these things back so that all my previous work in iPhoto wasn't for nothing? Surely, Apple couldn't have just erased all this, as if it never happened, right?
Mac mini (Late 2012), OS X El Capitan (10.11)