Gather

Google Photos

Go to photos.google.com

Open up Google Photos in your browser.

photos.google.com in a browser

Select your pictures and download the originals

Select the photos you want, click the three-dot menu, and hit Download. Your photos will start downloading as a .zip file. This can take a while, so grab a drink.

Google Photos download menu

Open the .zip file to get your folder

Click the .zip file to open it. A folder will appear with all your pictures inside.

Zip file next to the extracted folder

You're all set

Now all you need to do is create your book and drag the folder in.