diff --git a/wsgi.py b/wsgi.py
index 8425b77..7f75311 100644
--- a/wsgi.py
+++ b/wsgi.py
@@ -156,9 +156,9 @@ def plot(
     # Convert plot to SVG image
     imgdata = io.StringIO()
     fig.savefig(imgdata, format="svg")
-    svgImage.seek(0)  # rewind the data
+    imgdata.seek(0)  # rewind the data
 
-    return svgImage.read()
+    return imgdata.read()
 
 
 @app.route("/")