When you save photos that are shared with you, there are two places where you can find them i.e. "The Carousel Timeline" and "In Dropbox".
In the Carousel Timeline: Your saved photos will appear in your Carousel Timeline and organized by the date they were taken. You can also merge these photos into your Carousel events with date and time.
In Dropbox: Your saved photos will be added to the "Carousel" folder located in your Dropbox. Within the "Carousel" folder, your photos will be stored in folders named after the person who shared the photos.