You can add photos to your Monthbook or Monthly Mini on Chatbooks.com.
How do I add photos on the web?
Log in to Chatbooks.com
Click Home at the top of the page, or click Account and then My Books
Click into your subscription, then click the book you want to add photos to
Click the + button
Choose where to add photos from: your Computer, Your Mobile Device (scan a QR code to add photos from your phone), or Google Photos
Can I edit my photos after adding them?
Click a photo to add a caption, adjust the date and location, or change the page layout
To change more than one photo at a time, choose an option under Batch actions
Once your book has 30–60 pages, you can send it to print.
Using the app? See How do I add photos to my subscription book?