D2AMobile is a free Android app developed by DAICOLO CO.LTD. It is designed to be used as a companion app for graduation albums, specifically for those who have an "album ID" printed on their album colophon (endpaper). Without the album ID, the app cannot be used. You can find more information about this in the description of the yearbook.

The app contains many photos that did not fit into the album, and allows for free scaling of the photos. It also features music and narrated slide show playback, and can even record music such as the school song. It's worth noting that some of the content may differ depending on the school.

Overall, D2AMobile is a useful app for those who want to view additional photos and relive the memories of their graduation album.