links sollte nun die gesamte APP_URL enthalten

app/Http/Controllers/Api/SparkboothUploadController.php

@@ -57,7 +57,8 @@ class SparkboothUploadController extends Controller
                 $gallery,
                 $file,
                 $base64Payload,
-                $request->input('filename')
+                $request->input('filename'),
+                $request
             );
         } catch (RuntimeException $exception) {
             return $this->respondError($request, $exception->getMessage(), Response::HTTP_UNPROCESSABLE_ENTITY, $gallery);
@@ -177,7 +178,8 @@ class SparkboothUploadController extends Controller
         Gallery $gallery,
         ?UploadedFile $file,
         ?string $base64Payload,
-        ?string $preferredFilename
+        ?string $preferredFilename,
+        Request $request
     ): array {
         $directory = trim($gallery->images_path, '/');
 
@@ -192,7 +194,7 @@ class SparkboothUploadController extends Controller
 
             $file->storeAs($directory, $filename, 'public');
 
-            return [$relativePath, asset('storage/'.$relativePath)];
+            return [$relativePath, $this->buildPublicUrl($relativePath, $request)];
         }
 
         if ($base64Payload === null) {
@@ -207,7 +209,7 @@ class SparkboothUploadController extends Controller
             throw new RuntimeException('Failed to store uploaded image.');
         }
 
-        return [$relativePath, asset('storage/'.$relativePath)];
+        return [$relativePath, $this->buildPublicUrl($relativePath, $request)];
     }
 
     /**
@@ -348,4 +350,13 @@ class SparkboothUploadController extends Controller
 
         return '<?xml version="1.0" encoding="UTF-8"?><rsp status="fail">'.$errorAttr.'</rsp>';
     }
+
+    private function buildPublicUrl(string $relativePath, Request $request): string
+    {
+        $relative = Str::start($relativePath, '/');
+
+        $root = config('app.url') ?: $request->getSchemeAndHttpHost();
+
+        return rtrim($root, '/').'/storage'.$relative;
+    }
 }