This was really helpful! I was trying to do this to create a list which also included image sources. For anyone looking into how to query images where the src is in the JSON file.

Take a look at https://github.com/gatsbyjs/gatsby/issues/8312#issuecomment-422926519 and https://github.com/gatsbyjs/gatsby/issues/8078#issuecomment-421540065 although the last one is not for JSON it might help to understand the issue.