Why aren't icons previewed in Finder on Mac?

[tadayuki]

nice to meet you. I'm Japanese, so I'm not good at English.

I'm using a Mac.
Icon does not appear for ".afphoto"

If you use Adobe Photoshop or Illustrator, an icon preview will appear.

Is there no icon preview in Affinity?

[Callum]

Hi Tadayuki,
Welcome to the forums

Please could you try going into the apps preferences and under General try enabling Save Thumbnails With Files.

Thanks
C