It's not. You can include images in markdown and markdown being markdown, the links are pretty easy to identify and then open. They don't have to, or better to

It's not. You can include images in markdown and markdown being markdown, the links are pretty easy to identify and then open. They don't have to, or better to say the shouldn't, be absolute http links. They can be just relative ones, and those will translate very nicely into file paths locally. If you just use a plain text editor you'll have to open them manually. A bit smarter one (e.g. most likely your IDE) will turn them into clickable file links. You're not losing anything but whoever looks at it on the web will have a lot better idea. And most people will look at it on the web first, before cloning the repo locally... Because it saves time.