diff --git a/src/config.js b/src/config.js
index 8f40b32bf..b000f97b4 100644
--- a/src/config.js
+++ b/src/config.js
@@ -90,7 +90,7 @@ const uniqueDnaTorrance = 10000;
 const preview = {
   thumbPerRow: 5,
   thumbWidth: 50,
-  imageRatio: format.width / format.height,
+  imageRatio: format.height / format.width,
   imageName: "preview.png",
 };