use congo thumb and cover images (#39)

#### 📖 Summary

<!-- Provide a summary of your changes. Describe the why and not how. -->

#### 📑 Test Plan

> 💡 Select your test plan for the code changes.

- [x] CI pipeline
- [ ] Custom test
- [ ] No test plan

##### Details / Justification

<!-- Add your test details or justification for missing tests here. -->

#### 📚 Additional Notes

<!-- A place for additional detail notes. -->

Co-authored-by: OCram85 <marco.blessing@googlemail.com>
Reviewed-on: #39

content/posts/pi-hole-as-docker-swarm-stack/index.md

@@ -16,8 +16,6 @@ tags: ['pihole', 'swarm', 'stack']
 # sharingLinks: [null]
 ---
 
-{{< figure src="black-hole.jpg" width="600" height="800" caption="Photo by Kamesh Vedula on Unsplash." >}}
-
 ## Intro
 
 Many of you already know [Pi-hole](https://pi-hole.net/) as a trusted DNS firewall solution in your home labs. But