In order to copy my files, easily to Google Photos, they must be in a flat directory structure. Doing this on my machine is a bit of a challenge, since I’m running Mac OS and trying to easily copy files on a read only external NTFS drive. The built in find functionality of the Finder window doesn’t really fit my needs. This approach will work on most unix systems.
Make a temporary directory, if you don’t already have one. For this scenario, I made a tmp directory in my home area. I have gotten myself into trouble often enough, that I will never use the system level /tmp directory ever again. From the Terminal in the top level directory where your images are, execute the following command(s):
mkdir ~/tmp find . -name '*.*' -exec cp {} ~/tmp \
This will copy all files from your target location to a temporary directory in your home/user area. Since a lot of my photos have different extensions, it is easiest to copy everything. The post on uploading to Google Photos will come later.