update readme

README.md

@@ -1,9 +1,17 @@
 #Page Meta-Data
 
-A plugin to add meta-data for each generated page in the format:
+A Pelican plugin to add the total page size to each generated page of your site.
 
-`index.html Tue 12 Nov 2019 03:52:15 PM CET 57.637KB`
+It calculates the weight of the HTML page including all image media and returns that in a human readable format (B, KB, MB).
 
-It calculates the weight of the HTML page including all image media. A time stamp reflecting the date of generation is also added.
+## Caveats:
+it currently is tailored to https://solar.lowtechmagazine.com and needs work in the following areas:
+
+* add options to show file name and generation time
+* properly handle subsites plugin (currently it only works for dither+subsites)* make sure it works with --relative-urls flag
+
+## Use:
+Add a div with id `page-size` to your template and `page_metadata` will place the result there.
+
+have fun!
 
-The data is appended at the end of the HTML, so nothing fancy for now.