Exclude certain images from dark mode filter #181

In the data carpentry image processing lesson, we recently came across an issue with image display in dark mode: datacarpentry/image-processing#349

The dark filter of varnish is applied to all images, which is problematic for an image processing lesson where we refer to specific pixel colours / image histograms etc. in the text (see the issue for examples and links). Is there a simple way to exclude particular images from the dark mode filter?

Thanks for your help!