Update README.md

Author: noogen

README.md

@@ -35,10 +35,14 @@ image_filter_water_pos [ top-left | top-right | center | bottom-left | bottom-ri
 # optional scale max ratio, default 1
 # becareful not to set this too high or it will use too much memory.
 # 
-# For example a 200KB JPEG file (1024x768) will take up 4MB of memory 
+# For example (during testing) a 200KB JPEG file (1024x768) will take up 4MB of memory 
 # when loaded; but when resampled to twice the the size, the memory 
 # use jumps to 20.1MB
 image_filter_scale_max 3;
+
+# If you think about it (mathematically), it make sense.  If you take a fully filled 4MB
+# memory block and increase it in 2-dimension (x*y) by 3x or 4MB * 3(x + y) = 36MB of
+# possible memory will be taken.
 ```
 
 # What does this solve?