From 698da84b4ac058e080668a08645e000f7009028e Mon Sep 17 00:00:00 2001
From: Frank <91616163+softhack007@users.noreply.github.com>
Date: Thu, 6 Nov 2025 23:09:09 +0100
Subject: [PATCH] prevent division by zero when image width or height is 0

catch error early before starting the decode/paint loop
---
 wled00/image_loader.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/wled00/image_loader.cpp b/wled00/image_loader.cpp
index ef283956..5ba7af0a 100644
--- a/wled00/image_loader.cpp
+++ b/wled00/image_loader.cpp
@@ -158,6 +158,12 @@ byte renderImageToSegment(Segment &seg) {
   if (millis() - lastFrameDisplayTime < wait) return IMAGE_ERROR_WAITING;
 
   decoder.getSize(&gifWidth, &gifHeight);
+  // bad gif size: prevent division by zero
+  if (gifWidth == 0 || gifHeight == 0) {
+    gifDecodeFailed = true;
+    USER_PRINTF("Invalid GIF dimensions: %dx%d\n", gifWidth, gifHeight);
+    return IMAGE_ERROR_GIF_DECODE;
+  }
   // softhack007: pre-calculate upscaling for speedup
   expandX = (seg_cols+(gifWidth-1)) / gifWidth;
   expandY = (seg_rows+(gifHeight-1)) / gifHeight;