Here's how to use Google Photos or Google+ to host photos for story maps:
- Go to https://photos.google.com, sign in, and upload photos via Google Photos. This step is optional; you can also upload photos directly to the Google+. Just start at step 2.
- Go to https://plus.google.com and sign in.
- Click the camera icon to create a new post from photos.
- Upload photos by dragging them onto the grey drop zone or clicking to open the file browser. If you previously uploaded photos to Google Photos they will be available here.
- Set the visibility of your post to `Public`
- Confirm a new post is created. An album named with today's date is created with your photos.
- In the story map builder, enter your Google account to browse your albums/photos (Story Map Cascade is shown below). You can see the album (named with the date of the Google+ post) in the first screenshot and the uploaded photos in the second.