gatsby-remark-images-custom-widths
A fork of gatsby-remark-images that displays images at a custom width, via the width attribute on an img in markdown:
<img src="./image.jpg" alt="My image" width="500px"/>The width used in this attribute overrides the maxWidth option passed into the plugin, so the image is processed based on the specified width. (Or more correctly, the set of responsive images generated are based around this width instead).