Update docs/classic-ui/images.md

Missed one.

Author: stevepiercy

docs/classic-ui/images.md

@@ -276,7 +276,7 @@ When the viewport width is greater than 800 pixels, the browser will use the lar
 
 ### Pixel density
 
-Another metric is the pixel density of the users screen.
+Another metric is the pixel density of the user's screen.
 This metric denotes the pixel density, or resolution, of an output device in dots per inch (DPI).
 
 ```json