UPDATE Sept 2017:
For anyone who finds this now, the facial recognition side of things can be handled in a number of ways. Personally, I back my photos up to a Synology NAS at home and then back that up to Amazon Drive. For the photos on the NAS, I actually sync. Although I sync one way, from NAS to Amazon, you could do it both ways which would give you a possibly easier way of uploading photos when you are travelling. Though you can also securely access the NAS remotely too so you can upload files to it from anywhere with just an Internet connection.
The NAS's web photo application does face recognition. I think that Amazon Photos does it too?
I have a similar amount of digital photos currently dating back to the start of the 1990's.
I'm not very disciplined at organising the photos and, as you've inferred, it is easy to end up with many duplicates in not careful.
In keeping with many photographers I know, I rename all my photos in a standard format and move them into a simple folder structure:
yyyy-mm-dd hh-mm-ss - <camera name>.jpg
This is done using a script based on the image EXIF metadata. I then keep these in folders organised by year/month with some month folders for special occasions, e.g.
2010
02-Feb
02-Skiing-Wengen
I also sometimes put a README.TXT file in the folder with notes.
Finally, I use GeoSetter to add geocoding using either a recorded GPS track or simply selected from the built-in Google maps. The nice thing about GeoSetter is that it can also set IPTC and/or XMP metadata into the image. It is this last part that is important since the embedded metadata is also recognised by Picassa which I use for facial recognition and for ease of browsing through. In truth, most of the time, I can find the pictures I want simply by finding the right year and month.
So this is on a NAS for me, but for your mother, a laptop 1TB drive would be fine - EXCEPT of course, that it needs backing up. If she has a decent broadband available, I would strongly recommend a cloud backup. I use CrashPlan as it is the cheapest for my needs with good, low-cost unlimited plans.
I would not trust treasured pictures only to a cloud service under any circumstances as you have NO COMEBACK whatsoever should they fold or even if they decide to delete your account (Google have done this to a number of people).
So to summarise:
- Use a script to rename by date/time
- Move into year/month folders to organise (could be easily scripted)
- Use a tool to add metadata to allow easy searching by location, tag, etc. (over time, this can take years, there is no hurry particularly)
- Backup to the cloud (and maybe a second copy to some spare capacity at your house - CrashPlan supports both) - this IS urgent! In fact, I'd recommend that you buy an external drive and take a copy ASAP to avoid inevitable loss.
- Have a copy on a cloud picture service if needed/wanted for sharing with others.
- Use something simple on her computer to allow local viewing if something more sophisticated than standard Windows tools needed. e.g. Picassa which understands the embedded metadata.
Sorry for the long-winded answer but I would personally not recommend simply dumping the pictures to a cloud picture service & doing some sorting is actually pretty straight-forward the way I've suggested and really doesn't take much effort to maintain going forwards.
In regards to duplicates, the renaming process quickly finds duplicates as they will now have the same name and when you try to move them into their folders, you will be told about the duplicate.
