Added param descriptions

Author: bachonk

README.md

@@ -18,8 +18,8 @@ In the file where you want to use the category, be sure to import the file.
 
 Call the method `setImageWithString:color:` on any `UIImageView` instance to set the image.
 
-The string will be interpreted as a name, and will use the initials of the first and last word in the string provided
-If a color is not provided, a random color will be generated.
+`string` is the string used to generate the initials. This should be a user's full name if available
+`color` is an optional paramter sets the background of the image. If not provided, a random color will be generated
 
 ### License