diff --git a/images/ch1-01-go-family-tree-x.dot b/images/ch1-01-go-family-tree-x.dot
deleted file mode 100644
index 5e71436..0000000
--- a/images/ch1-01-go-family-tree-x.dot
+++ /dev/null
@@ -1,26 +0,0 @@
-digraph G {
-	ranksep = .75; size = "7.5,7.5";
-	rankdir="LR";
-
-	node [shape=plaintext];
-
-	{
-		1970, 1972; 1985; 1989; 1992; 1995; 2007;
-		"B";
-	}
-
-	{
-		node [shape=circle];
-		"Go";
-	}
-
-	{ rank = same; "1970"; "B"; }
-	{ rank = same; "1972"; "C"; }
-	{ rank = same; "1985"; "Squeak"; }
-	{ rank = same; "1989"; "NewSqueak"; }
-	{ rank = same; "1992"; "Alef"; }
-	{ rank = same; "1995"; "Limbo"; }
-	{ rank = same; "2007"; "Go"; }
-
-	"B" -> "C" -> "Squeak" -> "NewSqueak" -> "Alef" -> "Limbo" -> "Go";
-}
diff --git a/images/ch1-01-go-family-tree-x.dot.png b/images/ch1-01-go-family-tree-x.dot.png
deleted file mode 100644
index feb8adb..0000000
Binary files a/images/ch1-01-go-family-tree-x.dot.png and /dev/null differ