diff --git a/README.md b/README.md
index 6aa1966..1e3049b 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,9 @@ Resizes and/or moves the contents of GameMaker (LTS / GM2022+) rooms.
 
 Mostly exists to help with the specific problem of "I want to resize my room towards top/left without moving my layers by hand". If you know, you know.
 
+| [![](media/before.png)](media/before.png) | [![](media/after.png)](media/after.png) |
+| - | - |
+
 Don't forget to backup your project before using the tool!
 
 ## Use ([web version](https://yal.cc/tools/gm/room-shifter/))
diff --git a/media/after.png b/media/after.png
new file mode 100644
index 0000000..90af939
Binary files /dev/null and b/media/after.png differ
diff --git a/media/before.png b/media/before.png
new file mode 100644
index 0000000..c7813a4
Binary files /dev/null and b/media/before.png differ
diff --git a/src/MainWeb.hx b/src/MainWeb.hx
index 5934f16..316b107 100644
--- a/src/MainWeb.hx
+++ b/src/MainWeb.hx
@@ -93,8 +93,8 @@ class MainWeb {
 			opt.offsetX = opt.sizeDX;
 			opt.sizeDY = int(opt_top);
 			opt.offsetY = opt.sizeDY;
-			opt.offsetX += int(opt_right);
-			opt.offsetY += int(opt_bottom);
+			opt.sizeDX += int(opt_right);
+			opt.sizeDY += int(opt_bottom);
 			opt.width = int(opt_width);
 			opt.height = int(opt_height);
 			opt.halign = flt(opt_halign);