I'm sure there are other ways, this one is just the easiest one I found for a no-coder like me.
So, you'll need to grab the markdown code for images:

So, the image.jpg part of that will need to be a link to the image. This means that the image needs to exist on the internet... somewhere.
I saw someone using imgur, so I tried it myself and it works.
So you head on to https://imgur.com/
You can post images anonymously there. So create your account and upload the image.

When uploaded go to the 3 dots on the upper right corner of the image and click on get share links and copy the one saying BBCode (Forums)

You paste the link into the parenthesis instead of the image.png, however you should delete the [img] part of the link at the beginning and at the end of the link.

Click on the preview button on the IH editor and see if everything is how you like it, and voila! :)
I love markdown, it is so simple.
Right? 🤪