Is it possible to preload photos / videos from iCloud before a presentation?

I use iCloud Photo Library with Optimize Storage. When trying to run a presentation/slideshow, it takes a long time before each picture or video is presented in high resolution. I know this is due to my local connection quality, but can’t do anything about that. So I wonder whether it is possible to temporarily preload the images I want to present without having to save a duplicate/backup copy of them first. The reason is that I would like to interact with the originals (mark favorites, tag people etc) while running the slideshow. Also, if I want to present the images in Apple Photos from my duplicate backup, Photos will offer to re-import them, which is not what I want…

Thank you for any help,

The iCloud Photo Library caching scheme is a black box, unfortunately, but I would think that if you run through the entire slideshow right before the presentation, all the images would be downloaded and stay downloaded at least until the space was needed again.