diff --git a/chart.png b/chart.png
deleted file mode 100644
index b341176aab..0000000000
Binary files a/chart.png and /dev/null differ
diff --git a/files/routes/static.py b/files/routes/static.py
index d8263f2059..16f4602fc5 100644
--- a/files/routes/static.py
+++ b/files/routes/static.py
@@ -104,10 +104,10 @@ def cached_chart(days):
 		days = int((nowstamp - firstsignup) / 86400)
 
 	if days > 31:
-		file = "/weekly_chart.png"
+		file = "/weekly_chart.webp"
 		day_cutoffs = [today_cutoff - 86400 * 7 * i for i in range(31)][1:]
 	else:
-		file = "/daily_chart.png"
+		file = "/daily_chart.webp"
 		day_cutoffs = [today_cutoff - 86400 * i for i in range(31)][1:]
 
 	day_cutoffs.insert(0, calendar.timegm(now))