diff --git a/desktop/src-tauri/src/lib.rs b/desktop/src-tauri/src/lib.rs
index f554ce967..02c2336a0 100644
--- a/desktop/src-tauri/src/lib.rs
+++ b/desktop/src-tauri/src/lib.rs
@@ -11,7 +11,7 @@ use managed_agents::{
     find_managed_agent_mut, load_managed_agents, save_managed_agents, start_managed_agent_process,
     stop_managed_agent_process, sync_managed_agent_processes, BackendKind,
 };
-use tauri::{Manager, RunEvent};
+use tauri::{http, Manager, RunEvent};
 use tauri_plugin_window_state::StateFlags;
 
 fn restore_managed_agents_on_launch(app: &tauri::AppHandle) -> Result<(), String> {
@@ -86,6 +86,75 @@ fn shutdown_managed_agents(app: &tauri::AppHandle) -> Result<(), String> {
     Ok(())
 }
 
+/// Proxy media requests through the Rust backend so they traverse the WARP tunnel.
+///
+/// WKWebView's networking stack bypasses WARP, causing 403s from Cloudflare Access.
+/// This handler routes `sprout-media://localhost/{path}` through reqwest, which
+/// runs in the Tauri process and goes through WARP.
+async fn handle_sprout_media(
+    app: &tauri::AppHandle,
+    request: &http::Request<Vec<u8>>,
+) -> http::Response<Vec<u8>> {
+    let state = app.state::<AppState>();
+    let base = relay::relay_api_base_url();
+
+    // Preserve path + query (thumbnails may have query params).
+    // Only proxy /media/ paths — reject anything else.
+    let path_and_query = request
+        .uri()
+        .path_and_query()
+        .map(|pq| pq.as_str())
+        .unwrap_or("/");
+
+    if !path_and_query.starts_with("/media/") {
+        return error_response(404, "not found");
+    }
+
+    let upstream_url = format!("{base}{path_and_query}");
+
+    let result = state
+        .http_client
+        .get(&upstream_url)
+        .timeout(std::time::Duration::from_secs(30))
+        .send()
+        .await;
+
+    match result {
+        Ok(resp) => {
+            let status = resp.status().as_u16();
+            let content_type = resp
+                .headers()
+                .get("content-type")
+                .and_then(|v| v.to_str().ok())
+                .unwrap_or("application/octet-stream")
+                .to_string();
+
+            match resp.bytes().await {
+                Ok(bytes) => http::Response::builder()
+                    .status(status)
+                    .header("content-type", &content_type)
+                    .body(bytes.to_vec())
+                    .unwrap_or_else(|_| error_response(500, "response build failed")),
+                Err(_) => error_response(502, "failed to read upstream body"),
+            }
+        }
+        Err(_) => error_response(502, "upstream request failed"),
+    }
+}
+
+fn error_response(status: u16, msg: &str) -> http::Response<Vec<u8>> {
+    http::Response::builder()
+        .status(status)
+        .header("content-type", "text/plain")
+        .body(msg.as_bytes().to_vec())
+        .unwrap_or_else(|_| {
+            http::Response::builder()
+                .status(500)
+                .body(Vec::new())
+                .unwrap()
+        })
+}
+
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     let app = tauri::Builder::default()
@@ -98,6 +167,13 @@ pub fn run() {
         )
         .plugin(tauri_plugin_websocket::init())
         .plugin(tauri_plugin_dialog::init())
+        .register_asynchronous_uri_scheme_protocol("sprout-media", |ctx, request, responder| {
+            let app = ctx.app_handle().clone();
+            tauri::async_runtime::spawn(async move {
+                let response = handle_sprout_media(&app, &request).await;
+                responder.respond(response);
+            });
+        })
         .manage(build_app_state())
         .setup(|app| {
             let app_handle = app.handle().clone();
diff --git a/desktop/src/features/messages/ui/MessageRow.tsx b/desktop/src/features/messages/ui/MessageRow.tsx
index 8e39ebc63..873cf548c 100644
--- a/desktop/src/features/messages/ui/MessageRow.tsx
+++ b/desktop/src/features/messages/ui/MessageRow.tsx
@@ -6,6 +6,7 @@ import type { UserProfileLookup } from "@/features/profile/lib/identity";
 import { UserProfilePopover } from "@/features/profile/ui/UserProfilePopover";
 import { KIND_STREAM_MESSAGE_DIFF } from "@/shared/constants/kinds";
 import { cn } from "@/shared/lib/cn";
+import { rewriteRelayUrl } from "@/shared/lib/mediaUrl";
 import { resolveMentionNames } from "@/shared/lib/resolveMentionNames";
 import { Markdown } from "@/shared/ui/markdown";
 import { MessageActionBar } from "./MessageActionBar";
@@ -172,7 +173,7 @@ export const MessageRow = React.memo(
                       setHasAvatarError(true);
                     }}
                     referrerPolicy="no-referrer"
-                    src={message.avatarUrl}
+                    src={rewriteRelayUrl(message.avatarUrl)}
                   />
                 ) : (
                   <div
@@ -198,7 +199,7 @@ export const MessageRow = React.memo(
                 setHasAvatarError(true);
               }}
               referrerPolicy="no-referrer"
-              src={message.avatarUrl}
+              src={rewriteRelayUrl(message.avatarUrl)}
             />
           ) : (
             <div
diff --git a/desktop/src/features/profile/ui/ProfileAvatar.tsx b/desktop/src/features/profile/ui/ProfileAvatar.tsx
index 5fb032bf7..57907dfc1 100644
--- a/desktop/src/features/profile/ui/ProfileAvatar.tsx
+++ b/desktop/src/features/profile/ui/ProfileAvatar.tsx
@@ -2,6 +2,7 @@ import { UserRound } from "lucide-react";
 import * as React from "react";
 
 import { cn } from "@/shared/lib/cn";
+import { rewriteRelayUrl } from "@/shared/lib/mediaUrl";
 
 type ProfileAvatarProps = {
   avatarUrl: string | null;
@@ -44,7 +45,7 @@ export function ProfileAvatar({
           setFailedAvatarUrl(avatarUrl);
         }}
         referrerPolicy="no-referrer"
-        src={avatarUrl}
+        src={rewriteRelayUrl(avatarUrl)}
       />
     );
   }
diff --git a/desktop/src/features/profile/ui/UserProfilePopover.tsx b/desktop/src/features/profile/ui/UserProfilePopover.tsx
index 68a54244e..eb6766855 100644
--- a/desktop/src/features/profile/ui/UserProfilePopover.tsx
+++ b/desktop/src/features/profile/ui/UserProfilePopover.tsx
@@ -1,6 +1,7 @@
 import * as React from "react";
 
 import { useUserProfileQuery } from "@/features/profile/hooks";
+import { rewriteRelayUrl } from "@/shared/lib/mediaUrl";
 import { usePresenceQuery } from "@/features/presence/hooks";
 import { PresenceBadge } from "@/features/presence/ui/PresenceBadge";
 import { Popover, PopoverContent, PopoverTrigger } from "@/shared/ui/popover";
@@ -42,7 +43,7 @@ export function UserProfilePopover({
                 alt={profile.displayName ?? "User avatar"}
                 className="h-10 w-10 shrink-0 rounded-xl object-cover shadow-sm"
                 referrerPolicy="no-referrer"
-                src={profile.avatarUrl}
+                src={rewriteRelayUrl(profile.avatarUrl)}
               />
             ) : (
               <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-xl bg-secondary text-xs font-semibold text-secondary-foreground shadow-sm">
diff --git a/desktop/src/shared/lib/mediaUrl.ts b/desktop/src/shared/lib/mediaUrl.ts
new file mode 100644
index 000000000..be5209126
--- /dev/null
+++ b/desktop/src/shared/lib/mediaUrl.ts
@@ -0,0 +1,28 @@
+/**
+ * Rewrite relay media URLs to use the sprout-media:// custom protocol.
+ *
+ * WKWebView's networking stack bypasses WARP, so direct <img src> requests
+ * to the relay get 403'd by Cloudflare Access. The sprout-media:// scheme
+ * routes fetches through the Rust backend, which goes through WARP.
+ *
+ * Detection is path-based: /media/{64-hex-chars}.{ext} is a Blossom BUD-01
+ * content-addressed URL. The 64-char lowercase hex SHA-256 hash makes this
+ * pattern unique to Blossom relays — false positives from other origins are
+ * practically impossible. This avoids needing async relay-URL initialization,
+ * eliminating race conditions with first render.
+ */
+
+// Matches: https://anything.com/media/{64-hex}.{ext}
+// Also matches thumbnails: /media/{64-hex}.thumb.jpg
+const RELAY_MEDIA_RE =
+  /^(?:https?:\/\/[^/]+)\/media\/([\da-f]{64}(?:\.thumb)?\.(?:jpg|png|gif|webp)(?:\?.*)?)$/;
+
+/**
+ * If `url` looks like a Blossom relay media URL, rewrite it to go through
+ * the sprout-media:// custom protocol. Otherwise return it unchanged.
+ */
+export function rewriteRelayUrl(url: string): string {
+  const m = RELAY_MEDIA_RE.exec(url);
+  if (!m) return url;
+  return `sprout-media://localhost/media/${m[1]}`;
+}
diff --git a/desktop/src/shared/ui/markdown.tsx b/desktop/src/shared/ui/markdown.tsx
index 66d7975f9..92f2581ad 100644
--- a/desktop/src/shared/ui/markdown.tsx
+++ b/desktop/src/shared/ui/markdown.tsx
@@ -4,6 +4,7 @@ import remarkBreaks from "remark-breaks";
 import remarkGfm from "remark-gfm";
 
 import { cn } from "@/shared/lib/cn";
+import { rewriteRelayUrl } from "@/shared/lib/mediaUrl";
 import remarkChannelLinks from "@/shared/lib/remarkChannelLinks";
 import remarkMentions from "@/shared/lib/remarkMentions";
 import { useChannelNavigation } from "@/shared/context/ChannelNavigationContext";
@@ -106,7 +107,7 @@ function createMarkdownComponents(
       <img
         alt={alt}
         className="max-h-96 rounded-2xl border border-border/70 object-cover"
-        src={src}
+        src={src ? rewriteRelayUrl(src) : src}
       />
     ),
     li: ({ children }) => <li className={listItemClassName}>{children}</li>,