diff --git a/codex-rs/app-server/tests/suite/v2/imagegen_extension.rs b/codex-rs/app-server/tests/suite/v2/imagegen_extension.rs
index e892507291..d2a4e43751 100644
--- a/codex-rs/app-server/tests/suite/v2/imagegen_extension.rs
+++ b/codex-rs/app-server/tests/suite/v2/imagegen_extension.rs
@@ -506,6 +506,7 @@ chatgpt_base_url = "{server_uri}"
 
 [features]
 imagegenext = true
+materialize_remote_images = true
 {code_mode_only}
 
 [model_providers.openai-custom]
diff --git a/codex-rs/app-server/tests/suite/v2/turn_start.rs b/codex-rs/app-server/tests/suite/v2/turn_start.rs
index 22552d9c74..5080937997 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -872,7 +872,7 @@ async fn turn_start_tracks_turn_event_analytics() -> Result<()> {
             thread_id: thread.id.clone(),
             client_user_message_id: None,
             input: vec![V2UserInput::Image {
-                url: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR4nGNgYAAAAAMAASsJTYQAAAAASUVORK5CYII=".to_string(),
+                url: "https://example.com/a.png".to_string(),
                 detail: None,
             }],
             responsesapi_client_metadata: Some(HashMap::from([(
diff --git a/codex-rs/core/config.schema.json b/codex-rs/core/config.schema.json
index b30b868bc7..90071f32de 100644
--- a/codex-rs/core/config.schema.json
+++ b/codex-rs/core/config.schema.json
@@ -512,6 +512,9 @@
             "local_thread_store_compression": {
               "type": "boolean"
             },
+            "materialize_remote_images": {
+              "type": "boolean"
+            },
             "memories": {
               "type": "boolean"
             },
@@ -4638,6 +4641,9 @@
         "local_thread_store_compression": {
           "type": "boolean"
         },
+        "materialize_remote_images": {
+          "type": "boolean"
+        },
         "memories": {
           "type": "boolean"
         },
@@ -5224,4 +5230,4 @@
   },
   "title": "ConfigToml",
   "type": "object"
-}
+}
\ No newline at end of file
diff --git a/codex-rs/core/src/session/mod.rs b/codex-rs/core/src/session/mod.rs
index 094745d622..32dd4c5f5c 100644
--- a/codex-rs/core/src/session/mod.rs
+++ b/codex-rs/core/src/session/mod.rs
@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::collections::HashMap;
 use std::collections::HashSet;
@@ -2588,8 +2589,14 @@ impl Session {
         turn_context: &TurnContext,
         items: &[ResponseItem],
     ) {
-        let items =
-            crate::image_url_materializer::materialize_conversation_item_images(items).await;
+        let items = if turn_context
+            .features
+            .enabled(Feature::MaterializeRemoteImages)
+        {
+            crate::image_url_materializer::materialize_conversation_item_images(items).await
+        } else {
+            Cow::Borrowed(items)
+        };
         let items = items.as_ref();
         {
             let mut state = self.state.lock().await;
diff --git a/codex-rs/core/tests/suite/code_mode.rs b/codex-rs/core/tests/suite/code_mode.rs
index 33a926f892..c46accd97e 100644
--- a/codex-rs/core/tests/suite/code_mode.rs
+++ b/codex-rs/core/tests/suite/code_mode.rs
@@ -2508,7 +2508,10 @@ image("data:image/png;base64,AAA");
 "#
     );
     let (_test, second_mock) =
-        run_code_mode_turn(&server, "use exec to return images", &code).await?;
+        run_code_mode_turn_with_config(&server, "use exec to return images", &code, |config| {
+            let _ = config.features.enable(Feature::MaterializeRemoteImages);
+        })
+        .await?;
 
     let req = second_mock.single_request();
     let items = custom_tool_output_items(&req, "call-1");
diff --git a/codex-rs/features/src/lib.rs b/codex-rs/features/src/lib.rs
index 8ee05aed21..6d71823949 100644
--- a/codex-rs/features/src/lib.rs
+++ b/codex-rs/features/src/lib.rs
@@ -183,6 +183,8 @@ pub enum Feature {
     ImageGeneration,
     /// Replace hosted image generation with the standalone image-generation extension.
     ImageGenExt,
+    /// Download remote images before recording them in conversation history.
+    MaterializeRemoteImages,
     /// Allow prompting and installing missing MCP dependencies.
     SkillMcpDependencyInstall,
     /// Removed compatibility flag for deleted skill env var dependency prompting.
@@ -1090,6 +1092,12 @@ pub const FEATURES: &[FeatureSpec] = &[
         stage: Stage::UnderDevelopment,
         default_enabled: false,
     },
+    FeatureSpec {
+        id: Feature::MaterializeRemoteImages,
+        key: "materialize_remote_images",
+        stage: Stage::UnderDevelopment,
+        default_enabled: false,
+    },
     FeatureSpec {
         id: Feature::SkillMcpDependencyInstall,
         key: "skill_mcp_dependency_install",
diff --git a/sdk/python/tests/test_app_server_inputs.py b/sdk/python/tests/test_app_server_inputs.py
index 42b63c5319..7741df0af4 100644
--- a/sdk/python/tests/test_app_server_inputs.py
+++ b/sdk/python/tests/test_app_server_inputs.py
@@ -24,7 +24,9 @@ def test_remote_image_input_is_materialized_before_responses_api(
             response_id="remote-image",
         )
 
-        with Codex(config=harness.app_server_config()) as codex:
+        config = harness.app_server_config()
+        config.config_overrides = ("features.materialize_remote_images=true",)
+        with Codex(config=config) as codex:
             result = codex.thread_start().run(
                 [
                     TextInput("Describe the remote image."),