Andrey After closer inspection, this does not seem to be a valid HEIC file. It does not have proper signature in the beginning of the file. I was not able to open it with File Explorer and Photos either.
After some digging I found out that this is actually a MOV video, not an image. Once renamed, it then gets processed by Tonfotos without issues.
So please just rename those files to .mov and it will work fine.