updated with formatting and links

Tools/Images/README.md

+## bmp2array4bit
 
-bmp2array4bit.py creates C (or C++) code that contains two arrays for adding images to four-bit sprites.  See Sprite_image_4bit for an example.
+bmp2array4bit.py reads a bmp file, and creates C (or C++) code that contains two arrays for adding images to four-bit sprites.  See [Sprite_image_4bit](../../examples/Sprite/Sprite_image_4bit) for an example.
 
-It is loosely based on Spark Fun's bmp2array script.
+It is loosely based on Spark Fun's bmp2array script, https://github.com/sparkfun/BMPtoArray/blob/master/bmp2array.py.  The bmp file format is documented in https://en.wikipedia.org/wiki/BMP_file_format.
 
-You'll need python 3.6 (the original use Python 2.7)
+You'll need python 3.6 (the original uses Python 2.7)
 
-usage: python bmp2array4bit.py [-v] star.bmp [-o myfile.c]
+`usage: python bmp2array4bit.py [-v] star.bmp [-o myfile.c]`
 
-Create the bmp file in Gimp from any image by:
+Create the bmp file in Gimp (www.gimp.org) from any image as follows:
 
-. Remove the alpha channel (if it has one)
+* Remove the alpha channel (if it has one)
         Layer -> Transparency -> Remove Alpha Channel
-. Set the mode to indexed.
+* Set the mode to indexed.
         Image -> Mode -> Indexed...
-. Select Generate optimum palette with 16 colors (max)
-. Export the file with a .bmp extension. Do NOT select options:
-    . Run-Length Encoded
-    . Compatibility Options: "Do not write color space information" 
-    . There are no Advanced Options available with these settings
+* Select Generate optimum palette with 16 colors (max)
+* Export the file with a .bmp extension. Do **NOT** select options:
+  * Run-Length Encoded
+  * Compatibility Options: "Do not write color space information" 
+  * There are no Advanced Options available with these settings
 
-I don't have photoshop so cannot help you with that.
+(There are other tools that will produce bmp files, and these should work provided you don't use run-length encoding or other advanced features).
 
 The first array produced is the palette for the image.
 The second is the image itself.