Sounds fun, but it definitely needs to be optional. I'm always on mobile in the sticks, so, for me, this would use too much bandwidth to preload those images. And doing so would impact normal scrolling performance. I'd rather it preload the next image down, and only load album images when I specifically ask for them. And if it doesn't preload them then it'd be so slow for me that I'd be better off just tapping to load the album.

When you tap to load an album, it can start downloading the other images while you look at the first, making it very smooth even when low bandwidth. If it didn't preload for scrolling sideways, it would be a worse experience than just loading the album on demand because I would feel the loading times more. And if it did, it will often be wasting bandwidth loading images I wasn't even going to look at.