From 64bfdff6c8111225a1c7e4480376738123f2cb15 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 10 Jan 2025 21:51:33 +1100
Subject: [PATCH] Only F mode starts with F

---
 src/PIL/SpiderImagePlugin.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/PIL/SpiderImagePlugin.py b/src/PIL/SpiderImagePlugin.py
index 3a87d009a..b26e1a996 100644
--- a/src/PIL/SpiderImagePlugin.py
+++ b/src/PIL/SpiderImagePlugin.py
@@ -267,7 +267,7 @@ def makeSpiderHeader(im: Image.Image) -> list[bytes]:
 
 
 def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
-    if im.mode[0] != "F":
+    if im.mode != "F":
         im = im.convert("F")
 
     hdr = makeSpiderHeader(im)