Image CDN should be aware of different doc versions

[jeffwang0516]

Describe the bug
Currently, changing the version of the document does not load images from specific branch.
i.e. all versions share the same image source from CDN https://download.pingcap.com

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
For each version maintained, have corresponding CDN path that stores the images from their branch
Take docs v5.2 as example:

• media dir https://github.com/pingcap/docs/tree/release-5.2/media
• CDN path: https://download.pingcap.com/v5.2/

Screenshots

• dev
  

• v5.2
  

The src of the image is always the same

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Related code:

website-docs/packages/download/utils.js

Line 17 in e612ad0

const IMAGE_CDN_PREFIX = 'https://download.pingcap.com/images'

[shczhen]

Hi @jeffwang0516 , thanks for your advise.

In current docs scenario, it's better to keep image consist. It is beneficial to the reuse of static resources. Besides, it's a big mission for doc team to update all image references.

But your advice is still very suitable for our next doc website idea. It's clear and helpful if we maintain common/versioned static media files for doc.