u/Free_Chain_540

I have just upgraded to a Mac Mini M4 with 512GB storage from a 2019 iMac with 2 TB drive. I have also bought a 2TB NVME SSD connected to the Mac mini with a thunderbolt cable.

I have migrated the old files and programs to the new computer using Migration Assistant but did not transfer the original photos due to size limitations of the 512 GB drive. I did set up an alias on the external drive for the photos library, but would now like to transfer the original photos to the external drive.

How do I do that in a way that it is recognised by iPhotos and the original photos remain on the external drive?