will Cloud Function affect Firebase Storage bandwidth usage?

Question

I am trying to figure out why firebase storage usage is far above my expectation

I only have few photo files in my Firebase storage, just around 75 photos, 100kb for

Answer 1

The part of the documentation you quoted that's relevant here is:

Cloud Functions accesses this image when it needs to run the container to execute your function.

The built images are being accessed by Cloud Functions in order to run your code that's built into the image. Although the documentation doesn't specify, I would guess that every cold start of a function requires a download of the image from the artifacts bucket. This would explain the usage on that bucket.