Are you sure the old images will be cleaned up?
I am new to Firebase and I am experiencing the exact same problem. But int my case the storage is growing and growing. I already have almost 4 GB (!!!!). The website is not even live. It's just a pretty normal next.js project with hosting. After the first days and a couple of deploys it was using 900MB. One day later already 1.5GB. and another day later 3.8GB. That doesn't look ok to me. The source hasn't really changed much.
I am using Functions and Hosting. Under "Hosting" I have deleted the release history (except the most current 2 one). I had to delete 20+ deploys in the history. I expected that this should clean up the Storage. But it didn't. Still growing... I am afraid that this has a huge effect on my bill sooner or later... This would be a show stopper for using Firebase for our company...
Any help highly appreciated. Thanks in advance...,