You can create collage pages featuring two photos on one page in the Chatbooks app on iOS and Android.
Collages are available for Monthbooks and 5x7 Baby's First Year books. They aren't available for Monthly Minis or 5x5 Baby's First Year books.
How do I make a collage on iOS?
From photos already in your book:
Tap on your book
Tap on a photo that you would like to collage
Tap "Collage"
Choose your 2nd photo and tap "Continue with 2 photos"
You can exit by tapping Edit Page in the upper left
From new photos:
Tap on your book
Tap the plus sign in the bottom-right corner
Select "Collage"
Choose your photo source (Book or Camera Roll)
Tap on the photos you'd like to use and tap "Continue with 2 photos"
Tap "Done"
How do I make a collage on Android?
From photos already in your book:
Tap into your book
Tap and hold the first photo you'd like in the collage
Tap the second photo
Tap Collage at the bottom of the screen
From new photos:
Tap into your book
Tap the blue + in the bottom right corner
Tap Add collage page and choose your photos
How do I edit a collage?
Tap on the collage page
Tap "Edit collage" at the top
From here, you can convert the photos back to individual pages, or replace an image
To replace an image, tap on the image you'd like to replace and tap "Change Image"
Select the source for the new image, tap the new image, and tap "Use this photo"
Tap "Save," then tap "Done" to go back to your book
How do I rearrange photos in a collage?
Tap into the collage page you'd like to edit
Tap "Edit collage" at the top of the screen
Tap and hold one of the images in the collage
Move your finger to where you want the photo to go
Tap "Save" to save changes
Using the website? See Can I make a collage by adding more than one photo per page on the web?