Backing up or migrating and sharing your Google Photos photos onto your Dropbox account is easy using PicBackMan Migrate tool. Following we have a quick guide to let you know how to migrate photos from Google Photos to Dropbox.
Here’s the video tutorial you can refer to
PicBackMan is a free photo/video uploader that helps you to keep your memories backed up to your favorite online services.
Users in 130+ countries have backed up.
... an excellent job of uploading more then 300GB of photos to 2 different services