diff --git a/docs/readme.md b/docs/readme.md
index ada0f0d2..79e4ce10 100644
--- a/docs/readme.md
+++ b/docs/readme.md
@@ -112,6 +112,7 @@ Release Notes
 ### Upcoming
 -   Changes
     - Firebase AI: Add support for Grounding with Google Maps.
+    - Firebase AI: Improved image configuration when using Nano Banana.
     - Storage: Added `ListAsync` API to list items and prefixes under a reference.
 
 ### 13.10.0
diff --git a/firebaseai/src/Candidate.cs b/firebaseai/src/Candidate.cs
index 9565291f..6a91a7ea 100644
--- a/firebaseai/src/Candidate.cs
+++ b/firebaseai/src/Candidate.cs
@@ -64,6 +64,46 @@ public enum FinishReason
     /// Token generation was stopped because the function call generated by the model was invalid.
     /// </summary>
     MalformedFunctionCall,
+    /// <summary>
+    /// Token generation stopped because generated images contain safety violations.
+    /// </summary>
+    ImageSafety,
+    /// <summary>
+    /// Image generation stopped because generated images have other prohibited content.
+    /// </summary>
+    ImageProhibitedContent,
+    /// <summary>
+    /// Image generation stopped because of other miscellaneous issue.
+    /// </summary>
+    ImageOther,
+    /// <summary>
+    /// The model was expected to generate an image, but none was generated.
+    /// </summary>
+    NoImage,
+    /// <summary>
+    /// Image generation stopped due to recitation.
+    /// </summary>
+    ImageRecitation,
+    /// <summary>
+    /// The response candidate content was flagged for using an unsupported language.
+    /// </summary>
+    Language,
+    /// <summary>
+    /// Model generated a tool call but no tools were enabled in the request.
+    /// </summary>
+    UnexpectedToolCall,
+    /// <summary>
+    /// Model called too many tools consecutively, thus the system exited execution.
+    /// </summary>
+    TooManyToolCalls,
+    /// <summary>
+    /// Request has at least one thought signature missing.
+    /// </summary>
+    MissingThoughtSignature,
+    /// <summary>
+    /// Finished due to malformed response.
+    /// </summary>
+    MalformedResponse,
   }
 
   /// <summary>
@@ -137,6 +177,16 @@ private static FinishReason ParseFinishReason(string str)
         "PROHIBITED_CONTENT" => Firebase.AI.FinishReason.ProhibitedContent,
         "SPII" => Firebase.AI.FinishReason.SPII,
         "MALFORMED_FUNCTION_CALL" => Firebase.AI.FinishReason.MalformedFunctionCall,
+        "IMAGE_SAFETY" => Firebase.AI.FinishReason.ImageSafety,
+        "IMAGE_PROHIBITED_CONTENT" => Firebase.AI.FinishReason.ImageProhibitedContent,
+        "IMAGE_OTHER" => Firebase.AI.FinishReason.ImageOther,
+        "NO_IMAGE" => Firebase.AI.FinishReason.NoImage,
+        "IMAGE_RECITATION" => Firebase.AI.FinishReason.ImageRecitation,
+        "LANGUAGE" => Firebase.AI.FinishReason.Language,
+        "UNEXPECTED_TOOL_CALL" => Firebase.AI.FinishReason.UnexpectedToolCall,
+        "TOO_MANY_TOOL_CALLS" => Firebase.AI.FinishReason.TooManyToolCalls,
+        "MISSING_THOUGHT_SIGNATURE" => Firebase.AI.FinishReason.MissingThoughtSignature,
+        "MALFORMED_RESPONSE" => Firebase.AI.FinishReason.MalformedResponse,
         _ => Firebase.AI.FinishReason.Unknown,
       };
     }
diff --git a/firebaseai/src/GenerationConfig.cs b/firebaseai/src/GenerationConfig.cs
index b8df13bb..926416c2 100644
--- a/firebaseai/src/GenerationConfig.cs
+++ b/firebaseai/src/GenerationConfig.cs
@@ -40,6 +40,7 @@ public readonly struct GenerationConfig
     private readonly JsonSchema _responseJsonSchema;
     private readonly List<ResponseModality> _responseModalities;
     private readonly ThinkingConfig? _thinkingConfig;
+    private readonly ImageConfig? _imageConfig;
 
     /// <summary>
     /// Creates a new `GenerationConfig` value.
@@ -168,6 +169,9 @@ public readonly struct GenerationConfig
     /// An error will be returned if this field is set for models that don't
     /// support thinking.
     /// </param>
+    /// <param name="imageConfig">
+    /// Configuration for the aspect ratio and size of generated images.
+    /// </param>
     public GenerationConfig(
         float? temperature = null,
         float? topP = null,
@@ -181,7 +185,8 @@ public GenerationConfig(
         Schema responseSchema = null,
         JsonSchema responseJsonSchema = null,
         IEnumerable<ResponseModality> responseModalities = null,
-        ThinkingConfig? thinkingConfig = null)
+        ThinkingConfig? thinkingConfig = null,
+        ImageConfig? imageConfig = null)
     {
       _temperature = temperature;
       _topP = topP;
@@ -197,6 +202,7 @@ public GenerationConfig(
       _responseModalities = responseModalities != null ?
           new List<ResponseModality>(responseModalities) : null;
       _thinkingConfig = thinkingConfig;
+      _imageConfig = imageConfig;
     }
 
     /// <summary>
@@ -222,7 +228,8 @@ internal Dictionary<string, object> ToJson()
         jsonDict["responseModalities"] =
             _responseModalities.Select(EnumConverters.ResponseModalityToString).ToList();
       }
-      if (_thinkingConfig != null) jsonDict["thinkingConfig"] = _thinkingConfig?.ToJson();
+      if (_thinkingConfig != null) jsonDict["thinkingConfig"] = _thinkingConfig.Value.ToJson();
+      if (_imageConfig != null) jsonDict["imageConfig"] = _imageConfig.Value.ToJson();
 
       return jsonDict;
     }
@@ -321,5 +328,81 @@ internal Dictionary<string, object> ToJson()
     }
   }
 
+  /// <summary>
+  /// Configuration options for generating images with Gemini models.
+  /// </summary>
+  public readonly struct ImageConfig
+  {
+    /// <summary>
+    /// The aspect ratio of generated images.
+    /// </summary>
+    public readonly struct AspectRatio
+    {
+      public string Value { get; }
+
+      /// <summary>
+      /// Constructs a custom AspectRatio, instead of one of the presets.
+      /// Note that the backend model needs to support the requested ratio.
+      /// </summary>
+      public AspectRatio(string value) { Value = value; }
+
+      public static readonly AspectRatio Square1x1 = new("1:1");
+      public static readonly AspectRatio Portrait9x16 = new("9:16");
+      public static readonly AspectRatio Landscape16x9 = new("16:9");
+      public static readonly AspectRatio Portrait3x4 = new("3:4");
+      public static readonly AspectRatio Landscape4x3 = new("4:3");
+      public static readonly AspectRatio Portrait2x3 = new("2:3");
+      public static readonly AspectRatio Landscape3x2 = new("3:2");
+      public static readonly AspectRatio Portrait4x5 = new("4:5");
+      public static readonly AspectRatio Landscape5x4 = new("5:4");
+      public static readonly AspectRatio Portrait1x4 = new("1:4");
+      public static readonly AspectRatio Landscape4x1 = new("4:1");
+      public static readonly AspectRatio Portrait1x8 = new("1:8");
+      public static readonly AspectRatio Landscape8x1 = new("8:1");
+      public static readonly AspectRatio Ultrawide21x9 = new("21:9");
 
+      public override string ToString() => Value;
+    }
+
+    /// <summary>
+    /// The size of images to generate.
+    /// </summary>
+    public readonly struct ImageSize
+    {
+      public string Value { get; }
+
+      /// <summary>
+      /// Constructs a custom ImageSize, instead of one of the presets.
+      /// Note that the backend model needs to support the requested size.
+      /// </summary>
+      public ImageSize(string value) { Value = value; }
+
+      public static readonly ImageSize Size512 = new("512");
+      public static readonly ImageSize Size1K = new("1K");
+      public static readonly ImageSize Size2K = new("2K");
+      public static readonly ImageSize Size4K = new("4K");
+
+      public override string ToString() => Value;
+    }
+
+    public AspectRatio? Ratio { get; }
+    public ImageSize? Size { get; }
+
+    /// <summary>
+    /// Creates a new `ImageConfig` with the given settings.
+    /// </summary>
+    public ImageConfig(AspectRatio? aspectRatio = null, ImageSize? imageSize = null)
+    {
+      Ratio = aspectRatio;
+      Size = imageSize;
+    }
+
+    internal Dictionary<string, object> ToJson()
+    {
+      Dictionary<string, object> jsonDict = new();
+      if (Ratio?.Value is string aspectRatio) jsonDict["aspectRatio"] = aspectRatio;
+      if (Size?.Value is string imageSize) jsonDict["imageSize"] = imageSize;
+      return jsonDict;
+    }
+  }
 }
diff --git a/firebaseai/testapp/Assets/Firebase/Sample/FirebaseAI/UIHandlerAutomated.cs b/firebaseai/testapp/Assets/Firebase/Sample/FirebaseAI/UIHandlerAutomated.cs
index 1cc30ad5..a2cc0ee8 100644
--- a/firebaseai/testapp/Assets/Firebase/Sample/FirebaseAI/UIHandlerAutomated.cs
+++ b/firebaseai/testapp/Assets/Firebase/Sample/FirebaseAI/UIHandlerAutomated.cs
@@ -188,6 +188,8 @@ protected override void Start()
         TestReadSecureFile,
         // Internal tests for Json parsing, requires using a source library.
         InternalTestBasicReplyShort,
+        InternalTestFinishReasonExpanded,
+        InternalTestImageConfigSerialization,
         InternalTestCitations,
         InternalTestBlockedSafetyWithMessage,
         InternalTestFinishReasonSafetyNoContent,
@@ -878,7 +880,9 @@ async Task TestGenerateImage(Backend backend)
     {
       var model = GetFirebaseAI(backend).GetGenerativeModel("gemini-2.5-flash-image",
         generationConfig: new GenerationConfig(
-          responseModalities: new[] { ResponseModality.Text, ResponseModality.Image })
+          responseModalities: new[] { ResponseModality.Text, ResponseModality.Image },
+          imageConfig: new ImageConfig(
+              aspectRatio: ImageConfig.AspectRatio.Square1x1))
       );
 
       GenerateContentResponse response = await model.GenerateContentAsync(
@@ -890,6 +894,7 @@ async Task TestGenerateImage(Backend backend)
       // We don't care much about the response, just that there is an image, and text.
       bool foundText = false;
       bool foundImage = false;
+      Texture2D image = new(1, 2);
       var candidate = response.Candidates.First();
       foreach (var part in candidate.Content.Parts)
       {
@@ -902,10 +907,13 @@ async Task TestGenerateImage(Backend backend)
           if (dataPart.MimeType.Contains("image"))
           {
             foundImage = true;
+            image.LoadImage(dataPart.Data.ToArray());
           }
         }
       }
       Assert($"Missing expected modalities. Text: {foundText}, Image: {foundImage}", foundText && foundImage);
+      // The height and width should match, since we requested a 1x1 aspect ratio.
+      AssertEq("Image dimensions should match.", image.height, image.width);
     }
 
     // Test generating an image via Imagen.
@@ -1541,6 +1549,61 @@ async Task InternalTestBasicReplyShort()
       ValidateUsageMetadata(response.UsageMetadata, 6, 7, 0, 0, 13);
     }
 
+    // Test that parsing a response with expanded FinishReason works.
+    Task InternalTestFinishReasonExpanded()
+    {
+      string jsonStr = @"{
+        ""candidates"": [{
+          ""content"": {
+            ""parts"": [{""text"": ""Hello""}],
+            ""role"": ""model""
+          },
+          ""finishReason"": ""IMAGE_SAFETY""
+        }]
+      }";
+      Dictionary<string, object> json = (Dictionary<string, object>)Json.Deserialize(jsonStr);
+      GenerateContentResponse response = GenerateContentResponse.FromJson(json, FirebaseAI.Backend.InternalProvider.VertexAI);
+
+      Assert("Response missing candidates.", response.Candidates.Any());
+      Candidate candidate = response.Candidates.First();
+      AssertEq("FinishReason", candidate.FinishReason, FinishReason.ImageSafety);
+
+      // Test another one
+      jsonStr = @"{
+        ""candidates"": [{
+          ""content"": {""parts"": []},
+          ""finishReason"": ""MALFORMED_RESPONSE""
+        }]
+      }";
+      json = (Dictionary<string, object>)Json.Deserialize(jsonStr);
+      response = GenerateContentResponse.FromJson(json, FirebaseAI.Backend.InternalProvider.VertexAI);
+      candidate = response.Candidates.First();
+      AssertEq("FinishReason", candidate.FinishReason, FinishReason.MalformedResponse);
+
+      return Task.CompletedTask;
+    }
+
+    // Test that ImageConfig serialization works as expected.
+    Task InternalTestImageConfigSerialization()
+    {
+      var imageConfig = new ImageConfig(ImageConfig.AspectRatio.Landscape16x9, ImageConfig.ImageSize.Size1K);
+      var json = imageConfig.ToJson();
+
+      AssertEq("ImageConfig.aspectRatio", json["aspectRatio"], "16:9");
+      AssertEq("ImageConfig.imageSize", json["imageSize"], "1K");
+
+      var genConfig = new GenerationConfig(imageConfig: imageConfig);
+      var genJson = genConfig.ToJson();
+
+      Assert("GenerationConfig missing imageConfig", genJson.ContainsKey("imageConfig"));
+      var imageConfigJson = genJson["imageConfig"] as Dictionary<string, object>;
+      Assert("imageConfig is not a dictionary", imageConfigJson != null);
+      AssertEq("imageConfigJson.aspectRatio", imageConfigJson["aspectRatio"], "16:9");
+      AssertEq("imageConfigJson.imageSize", imageConfigJson["imageSize"], "1K");
+      
+      return Task.CompletedTask;
+    }
+
     // Test that parsing a response including Citations works.
     // https://github.com/FirebaseExtended/vertexai-sdk-test-data/blob/main/mock-responses/unary-success-citations.json
     async Task InternalTestCitations()