fix markdown links to .png files that use a %%TOKEN%%

2018/algmyr/README.md

@@ -83,7 +83,7 @@ from hearing. But even without training you can easily read along with the
 printed characters and have the sound make sense with the look of the
 characters.
 
-See image [spoiler.png](%%REPO_URL%%/2018/algmyr/spoiler.png) for an example spectrogram.
+See image [spoiler.png](spoiler.png) for an example spectrogram.
 
 
 ### Limitations