Let's say there's a website or app with 20 images on the initial screen. For websites, we'd typically show images whenever they're available. Since the 20 images will likely all load at different times, the screen will repaint 20 times, once for each image.
I noticed a lot of mobile apps would wait until all the images are ready before showing them all at once. There would be a single repaint. If some images take too long to load, the apps will wait a bit, then show all the images that loaded successfully.
The trade-off is showing some images sooner vs showing everything all at once. Are there studies showing which one users prefer?