Display issue with gravstrap skeleton - image overflow, likely a bug

I love the ease of using the internal.md for sidebar.

I am using the right sidebar in the skeleton.

In the main page, I have .
The image is 800 by 800 pixels.

On a very large screen with a very big window, the right side of the displayed picture overlaps two characters of the text in the right sidebar.

Reducing the width of the window causes an increasing overlap until the sidebar goes beneath the main page.

Am I supposed to add some class to the image or is this a bug?