diff --git a/apps/desktop/src/store/profile.ts b/apps/desktop/src/store/profile.ts
index 67b708fb219..4c8ffc3540f 100644
--- a/apps/desktop/src/store/profile.ts
+++ b/apps/desktop/src/store/profile.ts
@@ -12,6 +12,7 @@ import {
   storedStringRecord
 } from '@/lib/storage'
 import { $gateway, ensureGatewayForProfile } from '@/store/gateway'
+import { setConnection } from '@/store/session'
 import type { ProfileInfo } from '@/types/hermes'
 
 // Canonical key for a profile: trimmed, empty → "default". Used everywhere we
@@ -178,6 +179,32 @@ export const $gatewaySwapTarget = atom<string | null>(null)
 
 let gatewaySwitch: Promise<void> | null = null
 
+// Keep the renderer's $connection (mode / baseUrl / profile) in lockstep with
+// the profile the live gateway is now on. $connection seeds from the PRIMARY
+// (window) backend at boot and otherwise only refreshes on a sleep/wake
+// reconnect — so activating a *background* profile left $connection describing
+// the primary, with the wrong `mode` for everything that branches on
+// local-vs-remote. Headline symptom: with a local primary and a remote pool
+// profile active, image attachments went out via the path-based `image.attach`
+// instead of `image.attach_bytes`, handing the remote gateway a client-only
+// path it can't resolve ("image not found: C:\…"), while the /api/fs/* file
+// browser and /api/media fetches targeted the wrong machine (#46651).
+// Best-effort: a failed descriptor fetch leaves the prior connection intact for
+// boot/reconnect to resync.
+async function syncConnectionToActiveProfile(profile: string): Promise<void> {
+  const getConnection = window.hermesDesktop?.getConnection
+
+  if (!getConnection) {
+    return
+  }
+
+  try {
+    setConnection(await getConnection(profile))
+  } catch {
+    // Leave the prior connection in place; boot/reconnect resyncs it later.
+  }
+}
+
 // Make `profile`'s backend the active gateway, lazily opening its socket if it
 // isn't live yet. Unlike the old single-socket swap, background profiles keep
 // their sockets — so their sessions keep streaming concurrently. A null/empty
@@ -218,6 +245,9 @@ export async function ensureGatewayProfile(profile: string | null | undefined):
     // the active gateway at it — without closing the profile you came from.
     await ensureGatewayForProfile(target)
     $activeGatewayProfile.set(target)
+    // The active backend just changed; resync $connection so remote-aware
+    // paths (image.attach_bytes vs image.attach, /api/fs/*, /api/media) follow.
+    await syncConnectionToActiveProfile(target)
   })()
 
   try {