diff --git a/analyze.sh b/analyze.sh
index b741bcb734fa4a7275945215c208f43c5b78c5bb..73a2f495a5491ceb336fa24355b8e2dca10d6312 100755
--- a/analyze.sh
+++ b/analyze.sh
@@ -6,8 +6,11 @@
 # Requirements: ImageMagick's identify and convert
 #
 
-# TODO: Move this outside of the script
-ASSUME_GREY=true
+# If true, input files are assumed to be greyscale.
+# If false, they are converted to greyscale before extracting statistics.
+if [ "." == ".$ASSUME_GREY" ]; then
+    ASSUME_GREY=true
+fi
 
 # TODO: Accept destination for identify-file as input