diff --git a/README.md b/README.md
index 4094c86..56a77d5 100644
--- a/README.md
+++ b/README.md
@@ -14,10 +14,24 @@ lid [option]... [source path] [output name]
 
 Options:<br>
 -f = output format, defaults to the recommended setting: png<br>
--q = quality, defaults to 90, only affects png & jpeg/jpg
+-m = mode, available: o4, o9, e. default: o4.
+-q = quality, defaults to 90, only affects jpeg/jpg
 
 source path = a path to an image file you want to dither<br>
 output name = the name of the file you would like to output, do not include file extension
 
+Lid works best outputting png files from any input. You will get the smallest file with the best quality this way.
+
+### Modes
+
+#### o4
+This is the lowest quality mode. It will produce the smallest file size. It is a four level ordered dither.
+
+#### o9
+This mode produces medium quality dithering, it is still a very noticeable effect but not as harsh as o4. It is a none level ordered dither.
+
+#### e
+This is the highest quality mode. It uses an error diffusion dither. The file size will be the largest of the bunch, but should still be a good reduction from a regular full color photograph.
+
 ## License
 Public domain. Use it, improve it, share it!