sfrmws wrote: … Going forward, is it better to just leave the photos system file on my laptop and not try to work with it on an external storage device? Importing photos from my iPhone should be simple but it doesn't seem to be.
The easiest and surest way to move pictures from phone to Mac is to use iCloud Photos. iCloud Photos is a synchronization service. When you engage iCloud Photos on a device, then the Photos Library on that device is kept exactly the same as the iCloud Photos Library.
So, for instance, when you take a picture with your iPhone, that picture is added to the iPhone's Photos Library. Then it is copied to the iCloud Photos Library. And then the picture is copied to the Mac's Photos Library and to Libraries on each of the other devices that you have connected. The Libraries are all kept the same. If you delete a picture on your Mac, then that picture is deleted at iCloud and on all the other devices. It's all automatic. If the devices are not plugged in to power, or if they are in heavy use, it may not happen immediately, but the devices synchronize without any work on your part.
As Yer_Man says, a Photos Library performs the same on an internal or external drive. That works especially well for a desktop Mac. But a MacBook moves around, and an external drive probably gets plugged and unplugged a lot. Because of that, if you have iCloud synchronization with a MacBook, then it works better if the connected Library is on the Internal Drive so that it can synchronize any time it wants. On my succession of MacBooks, I've always kept my connected Library on my Internal Drive, and I've moved lots of other files to an external drive to provide enough room inside. Portable SSDs have gotten so small and light, that I can easily carry one around with me. I periodically copy my Photos Library from my internal Pictures folder to an external drive for backup. I use a separate external drive for Time Machine.
Storage space can be a big problem for a large Photos Library. iCloud helps--on my phone, which doesn't have much storage, I use "Optimize Storage," which relies on the original image files being stored at iCloud so that it can keep smaller versions on the phone to save space. That way I can have all my favorite pictures with me all the time. I don't use "Optimize" on my Mac, because when I do a backup I want to get the full original files.
FYI, I have 200 GB of iCloud storage-- it costs $3/month. It seems worth it.
I hope this gives you some perspective on your options…
