Hello,
Steps to reproduce:
- Clone my project https://github.com/KonstantinSchuette/gatsby-anchor-bug
gatsby develop
- Fire up a incognito tab and navigate to
http://localhost:8000/page-2
- Then click on
GO TO ANCHOR
- Now you should see this:

I think the anchor plugins doesn't respect the height of the image, because the offset is equal to the height of the image.