diff --git a/app/Http/Controllers/Controller.php b/app/Http/Controllers/Controller.php
index 4e55faae..19f770b6 100644
--- a/app/Http/Controllers/Controller.php
+++ b/app/Http/Controllers/Controller.php
@@ -137,7 +137,7 @@ class Controller extends BaseController
         $image = Image::query()
             ->with('group')
             ->where('key', $request->route('key'))
-            ->where('extension', $request->route('extension'))
+            ->where('extension', strtolower($request->route('extension')))
             ->firstOr(fn() => abort(404));
         if (! $image->group->configs->get(GroupConfigKey::IsEnableOriginalProtection)) {
             abort(404);
@@ -176,7 +176,7 @@ class Controller extends BaseController
         /** @var Image $image */
         $image = Image::query()
             ->where('key', $request->route('key'))
-            ->where('extension', $request->route('extension'))
+            ->where('extension', strtolower($request->route('extension')))
             ->firstOr(fn() => abort(404));
 
         try {
diff --git a/app/Services/ImageService.php b/app/Services/ImageService.php
index 2f2228b9..2c1fde85 100644
--- a/app/Services/ImageService.php
+++ b/app/Services/ImageService.php
@@ -158,7 +158,7 @@ class ImageService
             'origin_name' => $file->getClientOriginalName(),
             'size' => $file->getSize() / 1024,
             'mimetype' => $file->getMimeType(),
-            'extension' => $file->extension(),
+            'extension' => strtolower($file->extension()),
             'width' => $img->width(),
             'height' => $img->height(),
             'is_unhealthy' => false,
diff --git a/routes/image.php b/routes/image.php
index 183f3149..e75ae5b6 100644
--- a/routes/image.php
+++ b/routes/image.php
@@ -7,6 +7,7 @@ use App\Enums\ConfigKey;
 
 $extensions = config('convention.app.'.ConfigKey::Group)[GroupConfigKey::AcceptedFileSuffixes];
 Route::middleware('cache.headers:public;max_age=2628000;etag')->group(function () use ($extensions) {
+    $extensions = array_merge(array_map('strtoupper', $extensions), array_map('strtolower', $extensions));
     Route::any('{key}.{extension}', [
         Controller::class, 'output',
     ])->where('extension', implode('|', $extensions));