Local image resizing not being displayed correctly (whereas it works for remote images)

[lolo120916]

Resizing a remote image, as indicated in #74 does work.

<img src="https://octodex.github.com/images/daftpunktocat-thomas.gif" width="200" height="100"/>
is correctly previewed as:

However, it does not work for a local image.

<img src="illustrations/image-8.png" width="250" height="300"/>

displays nothing, only the surrounding frame, (whereas it is correctly displayed in vscode native previewer):

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