Added note on imagemagick

README.md

@@ -30,6 +30,13 @@ Mac
 homebrew install zbar
 ```
 
+`imagemagick` is also needed to display the image through `Image.show()`. This may be installed using:
+
+Ubuntu
+```
+sudo apt install imagemagick
+```
+
 ## References
 
 This project utilises code from digitalduke (https://github.com/digitalduke/otpauth-migration-decoder)