diff --git a/crates/obscura-browser/src/page.rs b/crates/obscura-browser/src/page.rs
index 6e2c098..1735562 100644
--- a/crates/obscura-browser/src/page.rs
+++ b/crates/obscura-browser/src/page.rs
@@ -984,6 +984,10 @@ impl Page {
             PageError::NetworkError(e.to_string())
         })?;
 
+        // Store binary main resources (images, PDFs, octet-stream) base64 so
+        // Network.getResponseBody returns intact bytes. A UTF-8-lossy text store
+        // corrupts them (issue #340). Text-like types stay as text.
+        let main_is_binary = !is_text_like_content_type(response.content_type());
         self.record_network_event_with_body(
             url.as_str(),
             "GET",
@@ -991,7 +995,7 @@ impl Page {
             response.status,
             &response.headers,
             &response.body,
-            false,
+            main_is_binary,
         );
 
         if !response.redirected_from.is_empty() {
@@ -1469,6 +1473,23 @@ impl Page {
         })
     }
 
+    /// Make the body stored under `from_id` also retrievable under `to_id`.
+    /// The main navigation resource is stored under its internal request id, but
+    /// the CDP layer reports it to clients with the navigation's loaderId as the
+    /// requestId (Chrome's `requestId === loaderId` convention). Without this
+    /// alias, `Network.getResponseBody(loaderId)` misses and a client navigating
+    /// straight to an image or other resource cannot read the main-response body
+    /// (issue #340).
+    pub fn alias_response_body(&mut self, from_id: &str, to_id: &str) {
+        if from_id == to_id || self.response_bodies.contains_key(to_id) {
+            return;
+        }
+        if let Some(body) = self.response_bodies.get(from_id).cloned() {
+            self.response_bodies.insert(to_id.to_string(), body);
+            self.response_body_order.push_back(to_id.to_string());
+        }
+    }
+
     pub fn clear_response_bodies(&mut self) {
         self.response_bodies.clear();
         self.response_body_order.clear();
@@ -1678,6 +1699,29 @@ impl From<ObscuraNetError> for PageError {
     }
 }
 
+/// Whether a Content-Type is text-like and can be stored/returned as a UTF-8
+/// string. Everything else (images, PDF, fonts, octet-stream) is binary and must
+/// be base64-encoded so Network.getResponseBody returns intact bytes.
+fn is_text_like_content_type(content_type: Option<&str>) -> bool {
+    let ct = match content_type {
+        Some(c) => c.split(';').next().unwrap_or(c).trim().to_ascii_lowercase(),
+        // No Content-Type: assume text (matches the HTML-parse default).
+        None => return true,
+    };
+    if ct.is_empty() {
+        return true;
+    }
+    ct.starts_with("text/")
+        || ct == "application/json"
+        || ct == "application/xml"
+        || ct == "application/xhtml+xml"
+        || ct == "application/javascript"
+        || ct == "application/ecmascript"
+        || ct == "image/svg+xml"
+        || ct.ends_with("+json")
+        || ct.ends_with("+xml")
+}
+
 fn response_body_entry_limit() -> usize {
     std::env::var("OBSCURA_NETWORK_BODY_BUFFER_ENTRIES")
         .ok()
diff --git a/crates/obscura-cdp/src/domains/page.rs b/crates/obscura-cdp/src/domains/page.rs
index 62fbafc..dd84b5e 100644
--- a/crates/obscura-cdp/src/domains/page.rs
+++ b/crates/obscura-cdp/src/domains/page.rs
@@ -41,6 +41,26 @@ pub fn emit_navigation_events(
         .iter()
         .position(|ev| ev.resource_type == "Document" && ev.url == page_url);
 
+    // The main resource's body is stored under its internal request id, but the
+    // client sees it as `loader_id` (the requestId we report above). Alias it so
+    // Network.getResponseBody(loaderId) resolves, which is the only way a client
+    // navigating straight to an image/PDF/other resource can read the main body
+    // (issue #340). Also read the real Content-Type so frameNavigated reports the
+    // actual mime instead of a hardcoded text/html.
+    let mut nav_mime = "text/html".to_string();
+    if let Some(idx) = nav_idx {
+        let internal_id = &network_events[idx].request_id;
+        if let Some(ct) = network_events[idx].response_headers.get("content-type") {
+            // Strip any `; charset=...` parameter; frameNavigated wants the essence.
+            nav_mime = ct.split(';').next().unwrap_or(ct).trim().to_string();
+        }
+        if internal_id != loader_id {
+            if let Some(page) = ctx.get_page_mut(page_id) {
+                page.alias_response_body(internal_id, loader_id);
+            }
+        }
+    }
+
     // Playwright needs `Network.requestWillBeSent` for the main document to
     // arrive BEFORE `Page.frameNavigated` (issue #190).
     if let Some(idx) = nav_idx {
@@ -56,7 +76,7 @@ pub fn emit_navigation_events(
     let mut phase1 = vec![
         CdpEvent { method: "Page.lifecycleEvent".into(), params: json!({"frameId": frame_id, "loaderId": loader_id, "name": "init", "timestamp": ts}), session_id: es.clone() },
         CdpEvent { method: "Runtime.executionContextsCleared".into(), params: json!({}), session_id: es.clone() },
-        CdpEvent { method: "Page.frameNavigated".into(), params: json!({"frame": {"id": frame_id, "loaderId": loader_id, "url": page_url, "domainAndRegistry": "", "securityOrigin": page_url, "mimeType": "text/html", "adFrameStatus": {"adFrameType": "none"}}, "type": "Navigation"}), session_id: es.clone() },
+        CdpEvent { method: "Page.frameNavigated".into(), params: json!({"frame": {"id": frame_id, "loaderId": loader_id, "url": page_url, "domainAndRegistry": "", "securityOrigin": page_url, "mimeType": nav_mime, "adFrameStatus": {"adFrameType": "none"}}, "type": "Navigation"}), session_id: es.clone() },
         CdpEvent { method: "Runtime.executionContextCreated".into(), params: json!({"context": {"id": 2, "origin": page_url, "name": "", "uniqueId": format!("ctx-nav-{}", page_id), "auxData": {"isDefault": true, "type": "default", "frameId": frame_id}}}), session_id: es.clone() },
     ];
     let world_names: Vec<String> = if ctx.isolated_worlds.is_empty() {
@@ -359,6 +379,9 @@ pub async fn handle(
             Ok(json!({}))
         }
         "setInterceptFileChooserDialog" => Ok(json!({})),
+        // Obscura does not download files to disk, so there is no behavior to
+        // configure; ack it so clients that set it do not warn (issue #340).
+        "setDownloadBehavior" => Ok(json!({})),
         "getLayoutMetrics" => {
             // Obscura has no visual layout engine, so we return a fixed
             // 1280x720 viewport (Chrome's default) and try to derive the