Note: You need to have a gmail address to use Google Drive.
In the PosterMyWall editor, click 'Photo' and you’ll be given options for adding photos. Click 'Add from Google Drive'.
A window will pop-up, asking you to login to your email.
You’ll then be asked to provide permission for PosterMyWall to use your files, so you can gain access your Google Drive photos from PosterMyWall. Click 'Allow', and you’ll be taken to your drive. Granting this permission is necessary as the photos cannot be accessed otherwise.
Next, select your photo(s) and they will be instantly added to your design!