SDL: testgdk: Update icon filename for the new png image

SDL Commits
1 
From ea539c00755e653775d93a3c0c89d30fbbd4eee9 Mon Sep 17 00:00:00 2001
From: Ethan Lee <[EMAIL REDACTED]>
Date: Thu, 26 Feb 2026 10:44:58 -0500
Subject: [PATCH] testgdk: Update icon filename for the new png image

---
 VisualC-GDK/tests/testgdk/src/testgdk.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/VisualC-GDK/tests/testgdk/src/testgdk.cpp b/VisualC-GDK/tests/testgdk/src/testgdk.cpp
index d69e73e533db1..53e203d92d527 100644
--- a/VisualC-GDK/tests/testgdk/src/testgdk.cpp
+++ b/VisualC-GDK/tests/testgdk/src/testgdk.cpp
@@ -339,7 +339,7 @@ static bool SDLCALL GDKEventWatch(void* userdata, SDL_Event* event)
 int main(int argc, char *argv[])
 {
     int i;
-    const char *icon = "icon.bmp";
+    const char *icon = "icon.png";
     char *soundname = NULL;
     bool suppressdraw = false;