Remote images caching

Use case:

I am using Obsidian primarily on Windows and Android tablets.
I am creating a catalogue of items with pictures.
I do not want to store large number of images locally because it’s going to use up a lot of precious storage space, duplicating the images on each and every device. Instead I am embedding the images from an external service/server/site.
I would be grateful to learn how caching works in Obsidian.

Questions:

  1. Where does Obsidian store cached images (file system paths) on
    a) Android
    b) Windows
  2. How long are images cached by default?
  3. How to disable / enable image caching?
  4. How do I refresh a note to reflect changes on the remote machine (a.k.a. refresh the cache) ?
  5. Is there only one universal cache, or are there separate caches for images and other content, for example text?
  6. Is there a way to flush ( empty) the cache? If there are separate caches for images other content (for example text), is there a way to flush these separately, independently of one another?
  7. Is there a better way (syntax) or a better service to embed remote images?

Thank you in advance for your help!

Detailed info

My goal is to minimise storage space usage.
Plus, I’m only going to view a small fraction of (100ds of) notes when I need to recall info on a given item.
Thus I want my images to exist only in one place: on a remote machine or site.

How I experimented

I suspect there is caching happening because I opened a note with embedded image in reading mode,then exited Obsidian.
Then I replaced the remote image with different picture but with the same file name.
I opened the same note again and I saw the old image and not the newly uploaded one.

Syntax I’m using to embed external images:

<img src="https://images2.imgbox.com/65/8c/KYUAh8zC_o.jpg" width=70%>

Or

![Tradescantia Albiflora Nanouk](https://images2.imgbox.com/d9/5d/7A8YBEmd_o.jpg)

Information about all you want to know is not disclosed anywhere.
Caches can be purged by the OS on mobile devices.
Finally, you need more storage space.

On a personal note, for all important things I need local copies and do back-up at a GitHub repo.