Open Keynote on your Mac and choose the “Basic White” template
Choose “Blank” as the “Slide Layout”
In the upper right corner select “Document”
Choose “Custom Size” in the “Slide Size” dropdown
Type the video resolution you would like to achieve (7680 x 4320 for 8K, 3840 x 2160 for 4K)
Drag and drop your first picture into the empty document space. Ideally is has the same resolution
Duplicate the slide as many times as you need by right click on the small icon marked with “1” on the left sidebar and choosing “Duplicate”
Go to each slide individually click on the picture and choose “Replace” under “Format” “Image”
After replacing the first image with individual ones, select all thumbnails in the left sidebar
and select an transition (e.g. Clothesline) under “Add an effect”
Now you can preview your slideshow by pressing “Play” and pressing the space bar to step through the slides.
If you are happy with the result, please go to the menu bar and select “File > Export To > Movie”…
Retype the resolution here and define the time each image should stay on the screen under “Go to next slide after”
Name the file and export it. Open the amazing result in QuickTime Player. To add an audio track drag and drop it onto the video in QuickTime Player and save it again.
Now copy the resulting file on a USB Stick, attach it to your 8K TV and enjoy it.