How to add an image caption?

There is no simple way to do this in pure Markdown, but since Markdown supports HTML, you can do the following:

<figure>
    <img src='path_to_image.jpg' />
    <figcaption>Caption goes here</figcaption>
</figure>

are you sure there are no other tags to add as this text gets written on the post... ... ?

What do you mean? Only the text inside the <figcaption> tags should appear on the post, and it should appear directly under the image.

I mean that having this fragment inside a markdown post will appear as is, without any translation.

The fragment shouldn't appear as-is, it should be parsed as HTML.

If you're seeing the text as-is in the final post, please contact support with a link to the post and we will investigate and provide the fix.

I would like to know if blog template can support render images with caption directly?

For example, when I type !["img text"](https://img.com/test.jpg) it can be render with alt text and an image caption img text .

You can turn on the setting Create a caption from the image’s alt text on the services page of your dashboard. Does that help?

That's perfect, thank you for sharing