Our team is investigating an issue that was introduced in v1.0.7 where HEIC files are not recognized anymore.
While we investigate this, you can revert to version 1.0.5 as a workaround.
Topaz Gigapixel v1.0.5
Windows: [Download]
Mac: [Download]
Snapdragon: [Download]
We will post here once the issue is resolved.
Thank you
