[Website] Probable Bug in CI/CD

Some images are displayed incorrectly on staging. This issue occurs only on staging, i.e. arrows are shown locally and on the master branch. 

Steps to reproduce the issue:
1. Open any PR, for example [https://github.com/apache/beam/pull/17450](https://github.com/apache/beam/pull/17450) 

2. Follow the link to staging and open the Documentation page, or use this link: [http://apache-beam-website-pull-requests.storage.googleapis.com/17450/documentation/programming-guide/index.html#schemas](http://apache-beam-website-pull-requests.storage.googleapis.com/17450/documentation/programming-guide/index.html#schemas)

3. Notice that lines or empty images are displayed instead of orange arrows (Screenshots are included) 

!image-2022-04-29-12-18-19-719.png!

Imported from Jira [BEAM-14384](https://issues.apache.org/jira/browse/BEAM-14384). Original Jira may contain additional context.
Reported by: daria.bezkorovaina.