diff --git a/how_to b/how_to
index 8e3e1a3..f4b8ab5 100644
--- a/how_to
+++ b/how_to
@@ -138,6 +138,16 @@ ACPI GTX960M bug:
 Wallpapers :
     Find wallpapers with wrong dimensions:
         identify *.{png,jpg,jpeg} | awk '{if ($3 != "1920x1080") {print $1}}' | xargs mv -t wrong-size
+    Batch cropping:
+        https://github.com/pknowles/cropall
+        ./cropall.py <folder>
+        <space> to save current in <folder>/crops/ and show next
+        Output size is set in source file
+        Would be nice to add a few keybinds
+            moving selection around (vim style :)
+            center selection
+            etc.
+
 
 Drag & drop files:
     dragon : https://github.com/mwh/dragon