Google Cloud で基礎インフラストラクチャタスクを実行する：チャレンジラボ
You can't expect a novice to know how to do create a thumbnail function without teaching them how to do it. After doing the lab 3 times, I can say that the index.js script does not like the Pub/Sub topic's name to have any "-" or "_". A name like "qwiklabs-gcp-00-d5567adc0323_photos_topic" will give you errors. Just use something like "pubsubtopic".
You can't expect a novice to know how to do create a thumbnail function without teaching them how to do it.
Step 3 for creating a cloud function is unfair to those without any information beyond the practice labs. For example, the practice labs do not teach the different triggers for cloud functions and what they mean. I figured out that I needed to use the finalize trigger (and not the default which is set at archive), but it would have been better if at the very least the practice labs instructed the reader to check out the other triggers. Also, the practice lab didn't mark the function as complete until I specified the runtime to JSON 10. I don't know much about JSON, and I assumed 14 would be fine (this lab doesn't specify one to use). Maybe it was a fluke, but if 10 was required, the challenge lab or the practice labs should point out that versions are may not be compatible.