Image path handling should resolve paths as URIs

[agoose77]

In attempting to debug #1587, I created a simple demo:

# Main

![](2024-09-05 17-39-05.mp4)

I then realised that the link reference contains a space, which is prohibited by the CommonMark spec (and is generally link-like behaviour). So, I updated the example to use autolink syntax which is a suggested mechanism of escaping whitespace:

# Main

![](<2024-09-05 17-39-05.mp4>)

I could also have written

![](2024-09-05%2017-39-05.mp4)

but the bracket syntax is more readable (to me).

This failed to load the image. It looks like we're just appending the urlSource to the path for local files rather than URL decoding the name.