diff --git a/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/MainActivity.java b/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/MainActivity.java
index e9f32a927cc..ac14270ed51 100644
--- a/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/MainActivity.java
+++ b/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/MainActivity.java
@@ -19,6 +19,7 @@
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
+import android.os.Process;
 import android.provider.MediaStore;
 import android.system.ErrnoException;
 import android.system.Os;
@@ -44,6 +45,8 @@
 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
 import org.pytorch.executorch.LlamaCallback;
 import org.pytorch.executorch.LlamaModule;
 
@@ -71,15 +74,16 @@ public class MainActivity extends AppCompatActivity implements Runnable, LlamaCa
   private Handler mMemoryUpdateHandler;
   private Runnable memoryUpdater;
   private int promptID = 0;
-
+  private long startPos = 0;
   private static final int CONVERSATION_HISTORY_MESSAGE_LOOKBACK = 2;
+  private Executor executor;
 
   @Override
   public void onResult(String result) {
     if (result.equals(PromptFormat.getStopToken(mCurrentSettingsFields.getModelType()))) {
       return;
     }
-    if (result.equals("\n\n")) {
+    if (result.equals("\n\n") || result.equals("\n")) {
       if (!mResultMessage.getText().isEmpty()) {
         mResultMessage.appendText(result);
         run();
@@ -150,6 +154,12 @@ private void setLocalModel(String modelPath, String tokenizerPath, float tempera
               + (float) loadDuration / 1000
               + " sec."
               + " You can send text or image for inference";
+
+      if (mCurrentSettingsFields.getModelType() == ModelType.LLAVA_1_5) {
+        ETLogging.getInstance().log("Llava start prefill prompt");
+        startPos = mModule.prefillPrompt(PromptFormat.getLlavaPresetPrompt(), 0, 1, 0);
+        ETLogging.getInstance().log("Llava completes prefill prompt");
+      }
     }
 
     Message modelLoadedMessage = new Message(modelInfo, false, MessageType.SYSTEM, 0);
@@ -241,6 +251,7 @@ protected void onCreate(Bundle savedInstanceState) {
     setupCameraRoll();
     startMemoryUpdate();
     setupShowLogsButton();
+    executor = Executors.newSingleThreadExecutor();
   }
 
   @Override
@@ -546,6 +557,32 @@ private void showMediaPreview(List<Uri> uris) {
       imageViews.get(i).setVisibility(View.VISIBLE);
       imageViews.get(i).setImageURI(mSelectedImageUri.get(i));
     }
+
+    // For LLava, we want to call prefill_image as soon as an image is selected
+    // Llava only support 1 image for now
+    if (mCurrentSettingsFields.getModelType() == ModelType.LLAVA_1_5) {
+      List<ETImage> processedImageList = getProcessedImagesForModel(mSelectedImageUri);
+      if (!processedImageList.isEmpty()) {
+        mMessageAdapter.add(
+            new Message("Llava - Starting image Prefill.", false, MessageType.SYSTEM, 0));
+        mMessageAdapter.notifyDataSetChanged();
+        Runnable runnable =
+            () -> {
+              Process.setThreadPriority(Process.THREAD_PRIORITY_MORE_FAVORABLE);
+              ETLogging.getInstance().log("Starting runnable prefill image");
+              ETImage img = processedImageList.get(0);
+              ETLogging.getInstance().log("Llava start prefill image");
+              startPos =
+                  mModule.prefillImages(
+                      img.getInts(),
+                      img.getWidth(),
+                      img.getHeight(),
+                      ModelUtils.VISION_MODEL_IMAGE_CHANNELS,
+                      startPos);
+            };
+        executor.execute(runnable);
+      }
+    }
   }
 
   private void addSelectedImagesToChatThread(List<Uri> selectedImageUri) {
@@ -618,24 +655,6 @@ private void onModelRunStopped() {
     mSendButton.setOnClickListener(
         view -> {
           addSelectedImagesToChatThread(mSelectedImageUri);
-          List<ETImage> processedImageList = getProcessedImagesForModel(mSelectedImageUri);
-          processedImageList.forEach(
-              image -> {
-                ETLogging.getInstance()
-                    .log(
-                        "Image preprocessed:"
-                            + " uri = "
-                            + image.getUri().getLastPathSegment()
-                            + ","
-                            + " width = "
-                            + image.getWidth()
-                            + ","
-                            + " height = "
-                            + image.getHeight()
-                            + ","
-                            + " bytes size = "
-                            + image.getBytes().length);
-              });
           String rawPrompt = mEditTextMessage.getText().toString();
           // We store raw prompt into message adapter, because we don't want to show the extra
           // tokens from system prompt
@@ -654,6 +673,8 @@ private void onModelRunStopped() {
               new Runnable() {
                 @Override
                 public void run() {
+                  Process.setThreadPriority(Process.THREAD_PRIORITY_MORE_FAVORABLE);
+                  ETLogging.getInstance().log("starting runnable generate()");
                   runOnUiThread(
                       new Runnable() {
                         @Override
@@ -664,31 +685,12 @@ public void run() {
                   long generateStartTime = System.currentTimeMillis();
                   if (ModelUtils.getModelCategory(mCurrentSettingsFields.getModelType())
                       == ModelUtils.VISION_MODEL) {
-                    ETLogging.getInstance().log("Running inference.. prompt=" + rawPrompt);
-                    if (!processedImageList.isEmpty()) {
-                      // For now, Llava only support 1 image.
-                      ETImage img = processedImageList.get(0);
-                      mModule.generate(
-                          processedImageList.get(0).getInts(),
-                          img.getWidth(),
-                          img.getHeight(),
-                          ModelUtils.VISION_MODEL_IMAGE_CHANNELS,
-                          rawPrompt,
-                          ModelUtils.VISION_MODEL_SEQ_LEN,
-                          MainActivity.this,
-                          false);
-                    } else {
-                      // no image selected, we pass in empty int array
-                      mModule.generate(
-                          new int[0],
-                          0,
-                          0,
-                          ModelUtils.VISION_MODEL_IMAGE_CHANNELS,
-                          rawPrompt,
-                          ModelUtils.VISION_MODEL_SEQ_LEN,
-                          MainActivity.this,
-                          false);
-                    }
+                    mModule.generateFromPos(
+                        mCurrentSettingsFields.getFormattedSystemAndUserPrompt(rawPrompt),
+                        ModelUtils.VISION_MODEL_SEQ_LEN,
+                        startPos,
+                        MainActivity.this,
+                        false);
                   } else {
                     String finalPrompt =
                         getTotalFormattedPrompt(getConversationHistory(), rawPrompt);
@@ -712,7 +714,7 @@ public void run() {
                   ETLogging.getInstance().log("Inference completed");
                 }
               };
-          new Thread(runnable).start();
+          executor.execute(runnable);
         });
     mMessageAdapter.notifyDataSetChanged();
   }
diff --git a/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/PromptFormat.java b/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/PromptFormat.java
index 4b450553236..640d3782128 100644
--- a/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/PromptFormat.java
+++ b/examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/PromptFormat.java
@@ -66,4 +66,9 @@ public static String getStopToken(ModelType modelType) {
         return "";
     }
   }
+
+  public static String getLlavaPresetPrompt() {
+    return "A chat between a curious human and an artificial intelligence assistant. The assistant"
+        + " gives helpful, detailed, and polite answers to the human's questions. USER: ";
+  }
 }