diff --git a/litellm/model_prices_and_context_window_backup.json b/litellm/model_prices_and_context_window_backup.json
index 9b1e60dff1a..2e21be86168 100644
--- a/litellm/model_prices_and_context_window_backup.json
+++ b/litellm/model_prices_and_context_window_backup.json
@@ -18782,6 +18782,48 @@
         },
         "web_search_billing_unit": "per_query"
     },
+    "gemini/gemini-3.1-flash-image": {
+        "input_cost_per_token": 2.5e-07,
+        "input_cost_per_token_batches": 1.25e-07,
+        "litellm_provider": "gemini",
+        "max_input_tokens": 65536,
+        "max_output_tokens": 32768,
+        "max_tokens": 32768,
+        "mode": "image_generation",
+        "output_cost_per_image": 0.045,
+        "output_cost_per_image_token": 6e-05,
+        "output_cost_per_token": 1.5e-06,
+        "output_cost_per_token_batches": 7.5e-07,
+        "rpm": 1000,
+        "tpm": 4000000,
+        "source": "https://ai.google.dev/gemini-api/docs/pricing#gemini-3.1-flash-image",
+        "supported_endpoints": [
+            "/v1/chat/completions",
+            "/v1/completions",
+            "/v1/batch"
+        ],
+        "supported_modalities": [
+            "text",
+            "image"
+        ],
+        "supported_output_modalities": [
+            "text",
+            "image"
+        ],
+        "supports_function_calling": false,
+        "supports_prompt_caching": true,
+        "supports_reasoning": false,
+        "supports_response_schema": true,
+        "supports_system_messages": true,
+        "supports_vision": true,
+        "supports_web_search": true,
+        "search_context_cost_per_query": {
+            "search_context_size_low": 0.014,
+            "search_context_size_medium": 0.014,
+            "search_context_size_high": 0.014
+        },
+        "web_search_billing_unit": "per_query"
+    },
     "gemini/gemini-3.1-flash-image-preview": {
         "input_cost_per_token": 2.5e-07,
         "input_cost_per_token_batches": 1.25e-07,
@@ -36781,6 +36823,22 @@
         "tpm": 8000000,
         "supports_image_size": false
     },
+    "vertex_ai/gemini-3-pro-image": {
+        "input_cost_per_image": 0.0011,
+        "input_cost_per_token": 2e-06,
+        "input_cost_per_token_batches": 1e-06,
+        "litellm_provider": "vertex_ai-language-models",
+        "max_input_tokens": 65536,
+        "max_output_tokens": 32768,
+        "max_tokens": 32768,
+        "mode": "image_generation",
+        "output_cost_per_image": 0.134,
+        "output_cost_per_image_token": 0.00012,
+        "output_cost_per_token": 1.2e-05,
+        "output_cost_per_token_batches": 6e-06,
+        "supports_reasoning": false,
+        "source": "https://docs.cloud.google.com/vertex-ai/generative-ai/docs/models/gemini/3-pro-image"
+    },
     "vertex_ai/gemini-3-pro-image-preview": {
         "input_cost_per_image": 0.0011,
         "input_cost_per_token": 2e-06,
@@ -36797,6 +36855,20 @@
         "supports_reasoning": false,
         "source": "https://docs.cloud.google.com/vertex-ai/generative-ai/docs/models/gemini/3-pro-image"
     },
+    "vertex_ai/gemini-3.1-flash-image": {
+        "input_cost_per_image": 0.00056,
+        "input_cost_per_token": 5e-07,
+        "litellm_provider": "vertex_ai-language-models",
+        "max_input_tokens": 65536,
+        "max_output_tokens": 32768,
+        "max_tokens": 32768,
+        "mode": "image_generation",
+        "output_cost_per_image": 0.0672,
+        "output_cost_per_image_token": 6e-05,
+        "output_cost_per_token": 3e-06,
+        "supports_reasoning": false,
+        "source": "https://cloud.google.com/vertex-ai/generative-ai/pricing#gemini-models"
+    },
     "vertex_ai/gemini-3.1-flash-image-preview": {
         "input_cost_per_image": 0.00056,
         "input_cost_per_token": 5e-07,
diff --git a/tests/test_litellm/test_utils.py b/tests/test_litellm/test_utils.py
index fddf1f4a0be..576f2f20242 100644
--- a/tests/test_litellm/test_utils.py
+++ b/tests/test_litellm/test_utils.py
@@ -4714,17 +4714,24 @@ class TestValidateEnvironmentTencent:
     "model",
     [
         "vertex_ai/gemini-2.5-flash-image",
+        "vertex_ai/gemini-3-pro-image",
         "vertex_ai/gemini-3-pro-image-preview",
+        "vertex_ai/gemini-3.1-flash-image",
         "vertex_ai/gemini-3.1-flash-image-preview",
         "gemini/gemini-2.5-flash-image",
         "gemini/gemini-3-pro-image",
         "gemini/gemini-3-pro-image-preview",
+        "gemini/gemini-3.1-flash-image",
         "gemini/gemini-3.1-flash-image-preview",
     ],
 )
 def test_gemini_image_models_do_not_support_reasoning(
     model: str, local_model_cost_map: None
 ) -> None:
+    assert model in litellm.model_cost, (
+        f"{model} is missing from the local model cost map. "
+        "Add its entry to litellm/model_prices_and_context_window_backup.json."
+    )
     assert litellm.supports_reasoning(model) is False, (
         f"{model} incorrectly classified as reasoning-capable. "
         "Add 'supports_reasoning: false' to its model_cost entry."