The default featured images for categories and tags is controlled by you! The rules are similar to the banner rotation.

Rules

1. The image dimensions MUST be 1038 pixels wide by 576 pixels tall.
2. Please attempt to keep the image below 200 KB. A little over is fine. A lot over is not.
3. Upload the image.
4. Determine the category or tag slug. The slug is the part WordPress uses in the URL. Hover over a link to the category or tag you want and in the status bar the slug will appear. Alternatively, view the category or tag page and in the URL bar the slug will appear. For the "At the Movies" category you will see https://wgom.org/category/at-the-movies/. The bolded part, at-the-movies is the slug for the "At the Movies" category. For the "Happy Birthday" tag you will see https://wgom.org/tag/happy-birthday/. The bolded part, happy-birthday is the slug for the "Happy Birthday" tag.
5. Prefix the title of the image with "active category/tag slug ". For example, to add an image named "Coffee" to the Cup of Coffee featured image rotation, the title given to the image would be "active category cup-of-coffee Coffee". For tags, if you wanted to add an image for the Cedar Rapids Kernels named "Veterans Memorial Stadium", the title given to the image would be "active tag kernels Veterans Memorial Stadium".