Thank you for your interest and for flagging the error! Indeed, I’ve observed the outdated “chainer” installation and updated it now. Sometimes modules and repositories are changing, and all Colabs depending on them should be updated :)

Please try following Colab: https://colab.research.google.com/drive/1cYxE0ScWWQ7HWVDza1oNDtTo4iBCI3gP?usp=sharing

This Colab has several additional features: New Chainer installation, multiple images upload, and also deletion of all image files using a command cell.

Please drop a message if it still don’t work.