Slow HEIC Viewing on Mac

Question

When viewing HEIC images with QuickLook from Finder on my MacBook Pro (2019) there is always a slight delay of almost a second. Other formats (jpg/png) work just fine.

When viewing the images in Photos they show up instantly.

Can this be fixed?

Answer 1

Since I found no fix I wrote a small app that uses macOS components to display the HEIC instantly.

Answer 2

Another possibility is using a third-party app such as ApolloOne. I have tried and succeeded in skimming through 50 HEIC files in just a couple of seconds. In contrast, QuickLook took nearly a whole second to view each individual HEIC file.