Error on transferring photos from iPhone onto Photos on Mac
False error

Yes, my method is correct. The problem isn't coming from WhatsApp and is more general to the process of transfering photos from Photos on iPhone toward Photos on Mac.

Here is the way I was able to get back my photo on My Mac, verify it was correctly transferred, and finally import it manually inside Photos.

On my Mac I made a search for any file with the name produced in the error window,
from Terminal I entered:

cd ~/Pictures/Photos\ Library.photoslibrary
find . -name "6c65168d-*"
./Masters/2018/11/05/20181105-103812/6c65168d-da6c-4df4-8239-28ab4d59c9dd.JPG
./Masters/2018/11/05/20181105-103830/6c65168d-da6c-4df4-8239-28ab4d59c9dd.JPG
./Masters/2018/11/05/20181105-111753/6c65168d-da6c-4df4-8239-28ab4d59c9dd.JPG


The "6c65168d-*" argument to find means find any file which name begins with 6c65168d- and print it.
The 3 result lines I got are correct and due to the fact I tried with smaller set of images 3 times to focus on the image causing the error.

Next, if I try to open any of these files, they do without any error within Preview, and moreover they can be easily imported within Photos without any error.

Conclusion

The error message is inappropriate and seems like an internal error within Photos on Mac or within the transfer process from iPhone to Mac.

I will continue the analysis of this stupid bug and report it to Apple.

Errors are already enough of a problem.

False errors are worse.