Add an example of using an image short code in 11ty v3.0.0 (eleventy-base-blog v9)

[Nooshu]

In eleventy-base-blog v8 a shortcode was used to insert the image into the md file.

I think it would be useful to have a similar example in v9 to help folks migrating from v8 to v9. Or is this no longer supported?

Thanks!