This is why there’s an ever evolving art of progressive/lazy image rendering. There are several techniques that involve populating a blurry or even polygonal version of an image that eventually resolves to the real image. The ultimate payload is larger, and the time to render is greater, but faster UX gratification is more satisfying.

This reminds me of a counterpoint to my top-level comment of how frustrating Apple’s progress bars are: way back in the early OS X days, they did user tests that showed people respond better to longer running progress disclosure than shorter running real progress. So they literally baked a delay into the OS X boot process that would make booting take longer but show a more predictable progress bar.