diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
new file mode 100644
index 0000000..229038a
--- /dev/null
+++ b/.github/copilot-instructions.md
@@ -0,0 +1,145 @@
+# gehGassi App - AI Coding Agent Instructions
+
+## Project Overview
+**gehGassi** is a .NET 9 MAUI cross-platform mobile app for a dog walking marketplace connecting dog owners with dog walkers. The app features dual user types (owners and walkers), real-time messaging, walk booking, payments, ratings, and a complex business workflow.
+
+## Architecture & Key Patterns
+
+### Project Structure (Clean Architecture)
+- **gehGassiApp** - Main MAUI app with Views, ViewModels, platform-specific code
+- **gehGassiApp.Core** - Business logic, services, interfaces  
+- **gehGassiApp.Domain** - Entity models, value objects
+- **gehGassiApp.Data** - Entity Framework Core, SQLite database, repository pattern
+- **gehGassi.LocalNotifications** - Custom notification library
+- **gehGassi.Dto** - Shared DTOs with backend (external project reference)
+
+### MVVM + DI Pattern
+- **BaseViewModel/MenuViewModel** - Inherit from these base classes for consistent patterns
+- **CommunityToolkit.Mvvm** - Uses `[ObservableProperty]` and `[RelayCommand]` attributes
+- **Dependency Injection** - All services registered in `MauiProgram.cs`, constructor injection throughout
+- **Page Lifecycle** - Override `InitializeAsync()` and `DisappearingAsync()` in ViewModels
+
+### Service Layer Architecture
+All business services follow `IService<T>` interface with standard CRUD operations:
+```csharp
+// Example service injection in ViewModels
+public MyViewModel(IWalkService walkService, IDialogService dialogService) { }
+```
+
+Key service types:
+- **Data Services** - Entity management (e.g., `IWalkService`, `IDogService`)
+- **Integration Services** - API communication (`ICommunicationService`)
+- **Platform Services** - Native features (`ILocationService`, `IDeviceInstallationService`)
+- **UI Services** - User interactions (`IDialogService`, `IPopupService`)
+
+### Configuration Management
+Environment-specific settings in `MauiProgram.cs`:
+- **DEBUG** - Local development server (`192.168.0.172:8548`)
+- **STAGING/DEBUGSTAGING** - Staging environment 
+- **RELEASE** - Production (`backend.gehgassi.com`)
+
+Application ID changes per environment:
+- Debug/Staging: `com.gehgassi.local`
+- Release: `com.gehgassi.gehgassi`
+
+## Critical Development Patterns
+
+### XAML Resources System
+**ALWAYS verify resource existence before use** - the app has strict resource validation:
+- **Converters**: Defined in `Resources/Converters/Converters.xaml` (30+ available)
+- **Styles**: Defined in `Resources/Styles/Styles.xaml` (H5_Red, BodyCaption variants, etc.)
+- **Reference**: See `gehGassiApp_Converters_And_Styles.md` for complete list
+
+Example of correct resource usage:
+```xml
+<!-- Correct - uses existing resources -->
+<Label Text="Error" Style="{StaticResource H5_Red}" 
+       IsVisible="{Binding HasError, Converter={StaticResource InvertedBoolConverter}}" />
+```
+
+### Data Binding Patterns
+- **Validation**: Use multi-binding for button states:
+```xml
+<Button Text="Save">
+    <Button.IsEnabled>
+        <MultiBinding Converter="{StaticResource AllTrueMultiConverter}">
+            <Binding Path="IsValid" />
+            <Binding Path="HasPhoto" />
+        </MultiBinding>
+    </Button.IsEnabled>
+</Button>
+```
+
+### Platform-Specific Code
+- **Android**: `Platforms/Android/` - Firebase services, permissions
+- **iOS**: `Platforms/iOS/` - Push notifications, App Store compliance
+- **Handlers**: Custom control behaviors in `MauiProgram.SetHandler()`
+
+### Local Database (EF Core + SQLite)
+- **Context**: `LocalDbContext` with automatic migrations
+- **Repository Pattern**: `IUnitOfWork` coordinates multiple services
+- **Sync Pattern**: Many services implement `ISyncPushPullService<T>` for offline capability
+
+## Build & Development
+
+### Build Configurations
+- **Debug** - Local development, APK format
+- **DebugStaging** - Staging with debug symbols
+- **Release** - Production, AAB format with AOT compilation
+- **Staging** - Pre-production testing
+
+### Build Commands
+```bash
+# Build for specific platform/config
+dotnet build -f net9.0-android -c Debug
+dotnet build -f net9.0-ios -c Release
+
+# Platform-specific from main project directory
+dotnet build gehGassiApp/gehGassiApp.csproj -f net9.0-android
+```
+
+### Critical Dependencies
+- **.NET 9** with MAUI 9.0.90
+- **Entity Framework Core 9.0.8** 
+- **CommunityToolkit.Mvvm 8.4.0** - MVVM framework
+- **Microsoft.AspNetCore.SignalR.Client** - Real-time communication
+- **Platform packages**: Xamarin.Firebase.Messaging (Android), various AndroidX libraries
+
+## Business Domain Knowledge
+
+### User Types & Workflows
+- **Dog Owners** - Create walk requests, book walkers, manage dogs, rate walkers
+- **Dog Walkers** - Browse requests, offer services, execute walks, receive payments
+- **Dual Users** - Can switch between owner/walker modes
+
+### Key Entities
+- **Walk** - Core business object with pickup/return addresses, timing, pricing
+- **PublicWalkRequest/Response** - Marketplace discovery system
+- **Rating** - Bidirectional rating system for quality assurance
+- **Conversation/Message** - In-app communication with SignalR real-time updates
+
+### Complex Features
+- **Payment Flow** - Integration with external payment providers, wallet system
+- **Location Services** - GPS tracking during walks, geofenced operations
+- **Push Notifications** - Azure Notification Hub for engagement
+- **Offline Sync** - Local-first architecture with background synchronization
+
+## Common Issues & Solutions
+
+### Resource Not Found Errors
+Always check `Resources/Converters/Converters.xaml` and `Resources/Styles/Styles.xaml` before adding new resources.
+
+### Navigation Patterns
+Use Shell-based navigation with query parameters:
+```csharp
+await Shell.Current.GoToAsync($"WalkView?walkId={walkId}");
+```
+
+### Memory Management
+Custom image handler prevents crashes on Android - avoid modifying existing image loading patterns without testing.
+
+### Platform Testing
+Test on both iOS and Android as business workflows have platform-specific behaviors (notifications, payments, camera).
+
+---
+**Note**: This app serves a real marketplace with financial transactions. Always test payment flows, rating systems, and user safety features thoroughly.
\ No newline at end of file
diff --git a/gehGassiApp/gehGassiApp/Resources/Text.de.resx b/gehGassiApp/gehGassiApp/Resources/Text.de.resx
index b1d5f2a..caa43a7 100644
--- a/gehGassiApp/gehGassiApp/Resources/Text.de.resx
+++ b/gehGassiApp/gehGassiApp/Resources/Text.de.resx
@@ -268,7 +268,7 @@
     <value>Meine Hunde</value>
   </data>
   <data name="Button_Done" xml:space="preserve">
-    <value>Fertig</value>
+    <value>Speichern</value>
   </data>
   <data name="Button_EditOffer" xml:space="preserve">
     <value>Angebot bearbeiten</value>
diff --git a/gehGassiApp/gehGassiApp/Resources/Text.resx b/gehGassiApp/gehGassiApp/Resources/Text.resx
index 85d9a63..2273d3b 100644
--- a/gehGassiApp/gehGassiApp/Resources/Text.resx
+++ b/gehGassiApp/gehGassiApp/Resources/Text.resx
@@ -268,7 +268,7 @@
     <value>My dogs</value>
   </data>
   <data name="Button_Done" xml:space="preserve">
-    <value>Done</value>
+    <value>Save</value>
   </data>
   <data name="Button_EditOffer" xml:space="preserve">
     <value>Edit offer</value>
diff --git a/gehGassiApp/gehGassiApp/ViewModels/ProfileViewModel.cs b/gehGassiApp/gehGassiApp/ViewModels/ProfileViewModel.cs
index 97c36f0..79ace36 100644
--- a/gehGassiApp/gehGassiApp/ViewModels/ProfileViewModel.cs
+++ b/gehGassiApp/gehGassiApp/ViewModels/ProfileViewModel.cs
@@ -75,6 +75,11 @@ namespace gehGassiApp.ViewModels
 		[ObservableProperty]
 		private bool _isNewPhoto;
 
+		/// <summary>
+		/// Hat der Benutzer ein Profilbild?
+		/// </summary>
+		public bool HasPhoto => !string.IsNullOrWhiteSpace(AppUser?.Photo);
+
 		/// <summary>
 		/// Liste der Länder
 		/// </summary>
@@ -266,6 +271,7 @@ namespace gehGassiApp.ViewModels
 			}
 			
 			CheckForChanges();
+			OnPropertyChanged(nameof(HasPhoto));
 		}
 
 		partial void OnIsNewPhotoChanged(bool value)
@@ -648,6 +654,12 @@ namespace gehGassiApp.ViewModels
 		private void OnAppUserPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
 		{
 			CheckForChanges();
+			
+			// HasPhoto aktualisieren wenn sich die Photo Property ändert
+			if (e.PropertyName == nameof(AppUser.Photo))
+			{
+				OnPropertyChanged(nameof(HasPhoto));
+			}
 		}
 
 		#endregion
diff --git a/gehGassiApp/gehGassiApp/ViewModels/ProfileWalkerViewModel.cs b/gehGassiApp/gehGassiApp/ViewModels/ProfileWalkerViewModel.cs
index 2cb36d9..cb49ada 100644
--- a/gehGassiApp/gehGassiApp/ViewModels/ProfileWalkerViewModel.cs
+++ b/gehGassiApp/gehGassiApp/ViewModels/ProfileWalkerViewModel.cs
@@ -88,6 +88,11 @@ namespace gehGassiApp.ViewModels
         [ObservableProperty]
         private bool _isNewPhoto;
 
+        /// <summary>
+        /// Hat der Benutzer ein Profilbild?
+        /// </summary>
+        public bool HasPhoto => !string.IsNullOrWhiteSpace(AppUser?.Photo);
+
         /// <summary>
         /// Liste der Länder
         /// </summary>
@@ -324,6 +329,7 @@ namespace gehGassiApp.ViewModels
             }
             
             CheckForChanges();
+            OnPropertyChanged(nameof(HasPhoto));
         }
 
         partial void OnWalkerProfileChanged(DogWalkerProfile value)
@@ -797,6 +803,12 @@ namespace gehGassiApp.ViewModels
         private void OnAppUserPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
         {
             CheckForChanges();
+            
+            // HasPhoto aktualisieren wenn sich die Photo Property ändert
+            if (e.PropertyName == nameof(AppUser.Photo))
+            {
+                OnPropertyChanged(nameof(HasPhoto));
+            }
         }
 
         /// <summary>
diff --git a/gehGassiApp/gehGassiApp/Views/ProfileView.xaml b/gehGassiApp/gehGassiApp/Views/ProfileView.xaml
index 2d6bdc5..d3b7149 100644
--- a/gehGassiApp/gehGassiApp/Views/ProfileView.xaml
+++ b/gehGassiApp/gehGassiApp/Views/ProfileView.xaml
@@ -174,6 +174,14 @@
 
                     </Grid>
 
+                    <Label
+                        Margin="{StaticResource MarginSmall}"
+                        HorizontalOptions="Center"
+                        IsVisible="{Binding HasPhoto, Converter={StaticResource InvertedBoolConverter}}"
+                        Style="{StaticResource H5_Red}"
+                        Text="Profilbild ist erforderlich"
+                        VerticalOptions="Start" />
+
                     <VerticalStackLayout
                         HorizontalOptions="Fill"
                         Spacing="0"
@@ -509,7 +517,7 @@
             <Button
                 x:Name="btnSave"
                 Margin="0,0,0,20"
-                AbsoluteLayout.LayoutBounds="0.5,1,300,60"
+                AbsoluteLayout.LayoutBounds="0.5,1,350,70"
                 AbsoluteLayout.LayoutFlags="PositionProportional"
                 Command="{Binding SaveCommand}"
                 HorizontalOptions="Center"
@@ -528,6 +536,7 @@
                         <Binding Path="IsValid" Source="{x:Reference mobileValidation}" />
                         <Binding Path="IsValid" Source="{x:Reference phoneValidation}" />
                         <Binding Path="AddressSelectionValid" />
+                        <Binding Path="HasPhoto" />
                         <Binding Path="IsNotBusy" />
                     </MultiBinding>
                 </Button.IsEnabled>
diff --git a/gehGassiApp/gehGassiApp/Views/ProfileWalkerView.xaml b/gehGassiApp/gehGassiApp/Views/ProfileWalkerView.xaml
index 1628aba..f02ad68 100644
--- a/gehGassiApp/gehGassiApp/Views/ProfileWalkerView.xaml
+++ b/gehGassiApp/gehGassiApp/Views/ProfileWalkerView.xaml
@@ -230,6 +230,14 @@
 
                     </Grid>
 
+                    <Label
+                        Margin="{StaticResource MarginSmall}"
+                        HorizontalOptions="Center"
+                        IsVisible="{Binding HasPhoto, Converter={StaticResource InvertedBoolConverter}}"
+                        Style="{StaticResource H5_Red}"
+                        Text="Profilbild ist erforderlich"
+                        VerticalOptions="Start" />
+
                     <VerticalStackLayout
                         Margin="{StaticResource MarginSection}"
                         HorizontalOptions="Fill"
@@ -1016,7 +1024,7 @@
             <Button
                 x:Name="btnSave"
                 Margin="0,0,0,20"
-                AbsoluteLayout.LayoutBounds="0.5,1,300,60"
+                AbsoluteLayout.LayoutBounds="0.5,1,350,70"
                 AbsoluteLayout.LayoutFlags="PositionProportional"
                 Command="{Binding SaveCommand}"
                 HorizontalOptions="Center"
@@ -1035,6 +1043,7 @@
                         <Binding Path="IsValid" Source="{x:Reference mobileValidation}" />
                         <Binding Path="IsValid" Source="{x:Reference phoneValidation}" />
                         <Binding Path="AddressSelectionValid" />
+                        <Binding Path="HasPhoto" />
                         <Binding Path="IsNotBusy" />
                     </MultiBinding>
                 </Button.IsEnabled>