diff --git a/app/Http/Controllers/Api/ApiController.php b/app/Http/Controllers/Api/ApiController.php
index 33b96f8a..c85adc06 100644
--- a/app/Http/Controllers/Api/ApiController.php
+++ b/app/Http/Controllers/Api/ApiController.php
@@ -10,6 +10,8 @@
 use App\Models\User;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Storage;
+use Illuminate\Support\Str;
 
 class ApiController extends Controller
 {
@@ -320,4 +322,27 @@ public function users(): JsonResponse
             'users' => $users,
         ]);
     }
+
+    /**
+     * Generate a presigned URL for avatar upload
+     */
+    public function generatePresignedUrlForAvatarUpload(Request $request): JsonResponse
+    {
+        $request->validate([
+            'avatar' => 'required|image',
+        ]);
+
+        $uuid = Str::uuid()->toString();
+        $fileName = $uuid . '.' . $request->avatar->extension();
+        $path = 'avatars/' . $fileName;
+        $presignedUrl = Storage::disk('s3')->temporaryUploadUrl(
+            $path,
+            now()->addMinutes(5)
+        );
+
+        return response()->json([
+            'presignedUrl' => $presignedUrl,
+            'path' => $path,
+        ]);
+    }
 }
diff --git a/app/Http/Controllers/DashboardAdminController.php b/app/Http/Controllers/DashboardAdminController.php
index 4cce2bce..6c1cca5f 100644
--- a/app/Http/Controllers/DashboardAdminController.php
+++ b/app/Http/Controllers/DashboardAdminController.php
@@ -16,7 +16,6 @@
 use Illuminate\Support\Facades\Request;
 use Illuminate\Support\Facades\Session;
 use Illuminate\Support\Facades\Storage;
-use Illuminate\Support\Str;
 use Inertia\Inertia;
 use Inertia\Response;
 use Spatie\Permission\Models\Role;
@@ -70,13 +69,13 @@ public function editUser(IlluminateRequest $request): RedirectResponse
         $validated = Request::validate([
             'firstname' => ['required', 'string', 'min:2', 'max:255'],
             'lastname' => ['required', 'string', 'min:2', 'max:255'],
-            'email' => ['required', 'string', 'email', 'min:3', 'max:255', 'unique:users,email,'.$user->id],
+            'email' => ['required', 'string', 'email', 'min:3', 'max:255', 'unique:users,email,' . $user->id],
             'email_confirm' => ['required', 'string', 'email', 'min:3', 'max:255', 'same:email'],
             'course_id' => ['required', 'integer', 'exists:courses,id'],
             'role_id' => ['array'],
             'is_disabled' => ['boolean'],
             'remove_avatar' => ['boolean'],
-            'avatar.*.file' => ['nullable', 'image', 'mimes:jpeg,png,jpg,gif'],
+            'avatar' => ['nullable', 'string'],
         ]);
 
         // check if all roles exists and not super admin if so add to roles array
@@ -107,18 +106,6 @@ public function editUser(IlluminateRequest $request): RedirectResponse
 
             // set avatar to null
             $validated['avatar'] = null;
-        } elseif (array_key_exists('avatar', $validated) && $validated['avatar'][0]) {
-            // get avatar file
-            $avatarFile = Request::file('avatar')[0]['file'];
-
-            // generate a uuid
-            $uuid = Str::uuid()->toString();
-
-            // store file in s3 bucket
-            $path = Storage::disk('s3')->put('/avatars/'.$uuid, $avatarFile);
-
-            // add avatar to validated array
-            $validated['avatar'] = $path;
         }
 
         // remove email_confirm, role_id and remove_avatar from array
@@ -134,7 +121,7 @@ public function editUser(IlluminateRequest $request): RedirectResponse
             $user->syncRoles($roles);
         }
 
-        Session::flash('success', 'Der Account <strong>'.$user->email.'</strong> wurde erfolgreich bearbeitet. Die Tabelle aktualisiert sich in wenigen Sekunden automatisch.');
+        Session::flash('success', 'Der Account <strong>' . $user->email . '</strong> wurde erfolgreich bearbeitet. Die Tabelle aktualisiert sich in wenigen Sekunden automatisch.');
 
         return Redirect::back();
     }
@@ -171,7 +158,7 @@ public function deleteUser(IlluminateRequest $request): RedirectResponse
             Storage::disk('s3')->delete($userTemp->avatar);
         }
 
-        Session::flash('success', 'Der Account <strong>'.$userTemp->email.'</strong> wurde erfolgreich gelöscht. Die Tabelle aktualisiert sich in wenigen Sekunden automatisch.');
+        Session::flash('success', 'Der Account <strong>' . $userTemp->email . '</strong> wurde erfolgreich gelöscht. Die Tabelle aktualisiert sich in wenigen Sekunden automatisch.');
 
         return Redirect::back();
     }
@@ -277,8 +264,8 @@ public function eventExecuteSubmit(IlluminateRequest $request): RedirectResponse
 
                     if (count($groups) > 0) {
                         // get max_groups and max_participants for course by request
-                        $maxGroups = $request->input('max_groups_'.$course->id);
-                        $maxParticipants = $request->input('max_participants_'.$course->id);
+                        $maxGroups = $request->input('max_groups_' . $course->id);
+                        $maxParticipants = $request->input('max_participants_' . $course->id);
 
                         $groupCourseDivision = new GroupCourseDivision($event, $course, $event->consider_alcohol, (int) $maxGroups, (int) $maxParticipants);
                         $groupCourseDivision->assign();
@@ -352,31 +339,16 @@ public function registerUser(): RedirectResponse
             'email' => ['required', 'string', 'email', 'min:3', 'max:255', 'unique:users'],
             'email_confirm' => ['required', 'string', 'email', 'min:3', 'max:255', 'same:email'],
             'course_id' => ['required', 'integer', 'exists:courses,id'],
-            'avatar.*.file' => ['nullable', 'image', 'mimes:jpeg,png,jpg,gif'],
+            'avatar' => ['nullable', 'string'],
         ]);
 
         // remove email_confirm from array
         unset($validated['email_confirm']);
 
-        // check if avatar is set
-        if (array_key_exists('avatar', $validated) && $validated['avatar'][0]) {
-            // get avatar file
-            $avatarFile = Request::file('avatar')[0]['file'];
-
-            // generate a uuid
-            $uuid = Str::uuid()->toString();
-
-            // store file in s3 bucket
-            $path = Storage::disk('s3')->put('/avatars/'.$uuid, $avatarFile);
-
-            // add avatar to validated array
-            $validated['avatar'] = $path;
-        }
-
         // create the user
         $user = User::create($validated);
 
-        Session::flash('success', 'Der Account <strong>'.$user->email.'</strong> wurde erfolgreich erstellt.');
+        Session::flash('success', 'Der Account <strong>' . $user->email . '</strong> wurde erfolgreich erstellt.');
 
         return Redirect::back();
     }
@@ -469,7 +441,7 @@ public function assignUser(): RedirectResponse
             'queue_position' => $queuePosition,
         ]);
 
-        Session::flash('success', 'Der Account <strong>'.$user->email.'</strong> wurde erfolgreich für das Event <strong>'.$event->name.'</strong>'.(array_key_exists('slot_id', $userRegistration) ? ' zu dem Slot <strong>'.$slot->name.'</strong>' : '').' zugewiesen.');
+        Session::flash('success', 'Der Account <strong>' . $user->email . '</strong> wurde erfolgreich für das Event <strong>' . $event->name . '</strong>' . (array_key_exists('slot_id', $userRegistration) ? ' zu dem Slot <strong>' . $slot->name . '</strong>' : '') . ' zugewiesen.');
 
         return Redirect::back();
     }
diff --git a/app/Models/User.php b/app/Models/User.php
index 4595f0a0..b8e27ac8 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -62,11 +62,13 @@ public function course(): BelongsTo
      */
     public function avatarUrl(): ?string
     {
-        // check if avatar is set
-        if ($this->avatar) {
-
-            // get immage from S3
-            return Storage::disk('s3')->url($this->avatar);
+        // check if avatar is set and file exists
+        if ($this->avatar && Storage::disk('s3')->exists($this->avatar)) {
+            // create presigned url
+            return Storage::disk('s3')->temporaryUrl(
+                $this->avatar,
+                now()->addMinutes(60)
+            );
         }
 
         return null;
diff --git a/resources/js/components/user/EditModal.vue b/resources/js/components/user/EditModal.vue
index f4286202..b1a4219b 100644
--- a/resources/js/components/user/EditModal.vue
+++ b/resources/js/components/user/EditModal.vue
@@ -197,11 +197,53 @@ const selectFormCourseOptions = useSelectFormCourseOptions(courses, true);
 const selectFormRoleOptions = useSelectFormRoleOptions(roles);
 const randomPlaceholderPerson = usePlaceholderPerson();
 
+const { uploadFileByPresignedUrl } = useS3();
+
 const close = () => {
   emits("close");
 };
 const editSubmitHandler = async () => {
-  Inertia.post(`/dashboard/admin/user/${user.id}`, editForm.value);
+  const avatarPath = ref<string | undefinded>();
+
+  if (editForm.value.avatar?.length) {
+    const formData = new FormData();
+    formData.append("avatar", editForm.value.avatar[0].file);
+
+    const response = await fetch(`/api/user/presigned-avatar-url`, {
+      method: "POST",
+      credentials: "include",
+      headers: {
+        "X-CSRF-TOKEN":
+          document
+            .querySelector("meta[name='csrf-token']")
+            ?.getAttribute("content") || "",
+      },
+      body: formData,
+    });
+
+    if (!response.ok) {
+      console.error("Failed to get presigned URL for avatar upload");
+      return;
+    }
+
+    const data = await response.json();
+
+    try {
+      await uploadFileByPresignedUrl(
+        formData.get("avatar"),
+        data.presignedUrl.url,
+      );
+      avatarPath.value = data.path;
+    } catch (error) {
+      console.error("Failed to upload avatar", error);
+      return;
+    }
+  }
+
+  Inertia.post(`/dashboard/admin/user/${user.id}`, {
+    ...editForm.value,
+    avatar: avatarPath.value,
+  });
   emits("submit");
 };
 </script>
diff --git a/resources/js/composables/useS3.ts b/resources/js/composables/useS3.ts
new file mode 100644
index 00000000..62f42ed3
--- /dev/null
+++ b/resources/js/composables/useS3.ts
@@ -0,0 +1,16 @@
+export default function () {
+  const uploadFileByPresignedUrl = async (file: File, presignedUrl: string) => {
+    const response = await fetch(presignedUrl, {
+      method: "PUT",
+      body: file,
+    });
+
+    if (!response.ok) {
+      throw new Error("Failed to upload file");
+    }
+  };
+
+  return {
+    uploadFileByPresignedUrl,
+  };
+}
diff --git a/resources/js/pages/Dashboard/Admin/Register.vue b/resources/js/pages/Dashboard/Admin/Register.vue
index 1293577f..bbac39c3 100644
--- a/resources/js/pages/Dashboard/Admin/Register.vue
+++ b/resources/js/pages/Dashboard/Admin/Register.vue
@@ -201,6 +201,9 @@ const getEventById = (id: number) => {
 
 const selectFormCourseOptions = useSelectFormCourseOptions(courses, true);
 const selectFormEventOptions = useSelectFormEventOptions(events);
+
+const { uploadFileByPresignedUrl } = useS3();
+
 const selectFormSlotOptions = computed(() => {
   const event = getEventById(assignForm.value.event_id);
 
@@ -213,7 +216,47 @@ const selectFormSlotOptions = computed(() => {
 const randomPlaceholderPerson = usePlaceholderPerson();
 
 const registerSubmitHandler = async () => {
-  Inertia.post("/dashboard/admin/register", registerForm.value);
+  const avatarPath = ref<string | undefinded>();
+
+  if (registerForm.value.avatar?.length) {
+    const formData = new FormData();
+    formData.append("avatar", registerForm.value.avatar[0].file);
+
+    const response = await fetch(`/api/user/presigned-avatar-url`, {
+      method: "POST",
+      credentials: "include",
+      headers: {
+        "X-CSRF-TOKEN":
+          document
+            .querySelector("meta[name='csrf-token']")
+            ?.getAttribute("content") || "",
+      },
+      body: formData,
+    });
+
+    if (!response.ok) {
+      console.error("Failed to get presigned URL for avatar upload");
+      return;
+    }
+
+    const data = await response.json();
+
+    try {
+      await uploadFileByPresignedUrl(
+        formData.get("avatar"),
+        data.presignedUrl.url,
+      );
+      avatarPath.value = data.path;
+    } catch (error) {
+      console.error("Failed to upload avatar", error);
+      return;
+    }
+  }
+
+  Inertia.post("/dashboard/admin/register", {
+    ...registerForm.value,
+    avatar: avatarPath.value,
+  });
 };
 
 const assignSubmitHandler = async () => {
diff --git a/resources/js/types/auto-imports.d.ts b/resources/js/types/auto-imports.d.ts
index c61fc46e..32da3350 100644
--- a/resources/js/types/auto-imports.d.ts
+++ b/resources/js/types/auto-imports.d.ts
@@ -9,6 +9,7 @@ declare global {
   const useColorMode: (typeof import("../composables/useColorMode"))["default"];
   const usePagesAsNavigation: (typeof import("../composables/usePagesAsNavigation"))["default"];
   const usePlaceholderPerson: (typeof import("../composables/usePlaceholderPerson"))["default"];
+  const useS3: (typeof import("../composables/useS3"))["default"];
   const useSelectFormCourseOptions: (typeof import("../composables/useSelectFormCourseOptions"))["default"];
   const useSelectFormEventOptions: (typeof import("../composables/useSelectFormEventOptions"))["default"];
   const useSelectFormRoleOptions: (typeof import("../composables/useSelectFormRoleOptions"))["default"];
diff --git a/resources/js/types/group.d.ts b/resources/js/types/group.d.ts
index 92bfb2e2..29fbb3f1 100644
--- a/resources/js/types/group.d.ts
+++ b/resources/js/types/group.d.ts
@@ -4,7 +4,6 @@ declare namespace App.Models {
     created_at: string /* Date */ | null;
     updated_at: string /* Date */ | null;
     event_id: number;
-    course_id: number | null;
     name: string;
     group_tutors?: GroupTutor[] | null;
     registrations?: Registration[] | null;
diff --git a/routes/web.php b/routes/web.php
index 6151987a..0b914278 100644
--- a/routes/web.php
+++ b/routes/web.php
@@ -32,7 +32,7 @@
     Route::get('/login', [AppController::class, 'login'])->name('app.login');
     Route::post('/login', [AppController::class, 'loginUser'])->name('app.loginUser');
 
-    Route::middleware(ActiveModule::class.':registration')->group(function () {
+    Route::middleware(ActiveModule::class . ':registration')->group(function () {
         Route::get('/register', [AppController::class, 'register'])->name('app.register');
         Route::post('/register', [AppController::class, 'registerUser'])->name('app.registerUser');
     });
@@ -84,13 +84,13 @@
             Route::post('/event/{event}/submit', [DashboardAdminController::class, 'eventExecuteSubmit'])->name('dashboard.admin.event.executeSubmit');
         });
 
-        Route::middleware(ActiveModule::class.':randomGenerator', 'can:manage random generator')->group(function () {
+        Route::middleware(ActiveModule::class . ':randomGenerator', 'can:manage random generator')->group(function () {
             Route::get('/random-generator', [DashboardAdminRandomGeneratorController::class, 'index'])->name('dashboard.admin.randomGenerator.index');
             Route::post('/random-generator', [DashboardAdminRandomGeneratorController::class, 'indexExecuteSubmit'])->name('dashboard.admin.randomGenerator.indexExecuteSubmit');
             Route::get('/random-generator/display', [DashboardAdminRandomGeneratorController::class, 'display'])->name('dashboard.admin.randomGenerator.display');
         });
 
-        Route::middleware(ActiveModule::class.':scoreSystem', 'can:manage score system')->group(function () {
+        Route::middleware(ActiveModule::class . ':scoreSystem', 'can:manage score system')->group(function () {
             Route::get('/score-system', [DashboardAdminScoreSystemController::class, 'index'])->name('dashboard.admin.scoreSystem.index');
             Route::post('/score-system', [DashboardAdminScoreSystemController::class, 'indexExecuteSubmit'])->name('dashboard.admin.scoreSystem.indexExecuteSubmit');
             Route::get('/score-system/display', [DashboardAdminScoreSystemController::class, 'display'])->name('dashboard.admin.scoreSystem.display');
@@ -123,16 +123,17 @@
 
         Route::middleware('can:manage users')->group(function () {
             Route::get('/users', [ApiController::class, 'users'])->name('api.users');
+            Route::post('/user/presigned-avatar-url', [ApiController::class, 'generatePresignedUrlForAvatarUpload'])->name('api.user.presignedAvatarUrl');
         });
     });
 
     Route::get('/registrations/{registration}', [ApiController::class, 'registrationsShow'])->name('api.registrations.show');
 
-    Route::middleware(ActiveModule::class.':randomGenerator', 'can:manage random generator')->group(function () {
+    Route::middleware(ActiveModule::class . ':randomGenerator', 'can:manage random generator')->group(function () {
         Route::get('/random-generator/state', [ApiController::class, 'randomGeneratorState'])->name('api.randomGeneratorState');
     });
 
-    Route::middleware(ActiveModule::class.':scoreSystem', 'can:manage score system')->group(function () {
+    Route::middleware(ActiveModule::class . ':scoreSystem', 'can:manage score system')->group(function () {
         Route::get('/score-system/state', [ApiController::class, 'scoreSystemState'])->name('api.scoreSystemState');
     });
 });