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README.md

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 Design files for a DIY fan controller that acts based on the main heat contributors' fan speeds.
 
-<img src="https://git.lukasschwarz.org/lukas/fancontroller/media/branch/master/case.jpg" width="40%">
+<img src="https://git.lukasschwarz.org/lukas/fancontroller/media/branch/master/case.jpg" width="40%" alt="Picture of the fan controller enclosure inside the PC case.">
 
 [Link to the more detailed article](https://lukasschwarz.org/projects/fan-controller/)