I created a bucket in Google Cloud Storage and uploaded some pics in the bucket. I made one pic public by adding AllUsers reading permission. Then I could see the picture whenever I hit that URL. Then I changed back the permissions to non-public to the same object. But When I hit the same URL, I could still see the picture. In theory it should not let me access the picture when it is turned back to no-public. Did anyone faced the saem problem?
Caching can account for this in a lot of cases; where your browser knows it loaded that picture only a few moments ago, so there is no point in contacting the server again to download the same picture so soon.
Pressing CTRL+F5 for a forced reload, using Private/Incognito modes in your browser, using a different browser, or clearing your browsers temporary files are all ways you can test this.