diff --git a/src/app/components/user-avatar/UserAvatar.css.ts b/src/app/components/user-avatar/UserAvatar.css.ts
index 34283d73..f93983cb 100644
--- a/src/app/components/user-avatar/UserAvatar.css.ts
+++ b/src/app/components/user-avatar/UserAvatar.css.ts
@@ -5,6 +5,12 @@ export const UserAvatar = style({
   backgroundColor: color.Secondary.Container,
   color: color.Secondary.OnContainer,
   textTransform: 'capitalize',
+  // Centre-crop to fill the (always-circular) avatar box, so a `scale`
+  // thumbnail (aspect-preserved — e.g. the 320 scale the profile hero requests
+  // because Synapse caps `crop` thumbnails at 96px) covers the circle exactly
+  // like a server-side crop would. No-op for the square crop thumbnails used
+  // by the small avatars elsewhere.
+  objectFit: 'cover',
 
   selectors: {
     '&[data-image-loaded="true"]': {
diff --git a/src/app/components/user-profile/UserHero.tsx b/src/app/components/user-profile/UserHero.tsx
index 899ecd1e..12b6c700 100644
--- a/src/app/components/user-profile/UserHero.tsx
+++ b/src/app/components/user-profile/UserHero.tsx
@@ -49,10 +49,7 @@ const shadeHex = (hex: string, amt: number): string => {
 // `Intl.RelativeTimeFormat` here because it follows the *browser*
 // locale, not the i18next-selected language; mixing those gives us
 // English «5 minutes ago» under a Russian UI.
-const formatLastSeen = (
-  ts: number,
-  t: ReturnType<typeof useTranslation>['t']
-): string => {
+const formatLastSeen = (ts: number, t: ReturnType<typeof useTranslation>['t']): string => {
   const now = Date.now();
   const diffMs = Math.max(0, now - ts);
   const mins = Math.floor(diffMs / 60_000);
@@ -71,7 +68,13 @@ const formatLastSeen = (
 type UserHeroProps = {
   userId: string;
   displayName?: string;
+  // Small (96px) cropped thumbnail for the collapsed hero — fast to fetch.
   avatarUrl?: string;
+  // Full-resolution avatar used ONLY in the expanded (~340px) state below, so
+  // the blown-up tile stays sharp instead of upscaling the 96px thumbnail.
+  // Mirrors RoomViewProfilePanel's full-res mobile fullview. Falls back to
+  // `avatarUrl` when absent.
+  avatarUrlExpanded?: string;
   presence?: UserPresence;
   encrypted?: boolean;
   onAvatarClick?: () => void;
@@ -87,6 +90,7 @@ export function UserHero({
   userId,
   displayName,
   avatarUrl,
+  avatarUrlExpanded,
   presence,
   encrypted,
   onAvatarClick,
@@ -137,7 +141,7 @@ export function UserHero({
     >
       <UserAvatar
         userId={userId}
-        src={avatarUrl}
+        src={avatarExpanded ? avatarUrlExpanded ?? avatarUrl : avatarUrl}
         alt={displayName ?? userId}
         renderFallback={() => (
           <span className={css.HeroAvatarFallback} style={{ backgroundImage: fallbackBg }}>
@@ -159,10 +163,9 @@ export function UserHero({
             css.HeroAvatarButton,
             avatarExpanded && css.HeroAvatarButtonExpanded
           )}
-          aria-label={t(
-            avatarExpanded ? 'Room.collapse_avatar' : 'Room.expand_avatar',
-            { defaultValue: avatarExpanded ? 'Close avatar' : 'Open avatar' }
-          )}
+          aria-label={t(avatarExpanded ? 'Room.collapse_avatar' : 'Room.expand_avatar', {
+            defaultValue: avatarExpanded ? 'Close avatar' : 'Open avatar',
+          })}
         >
           {avatarNode}
         </button>
diff --git a/src/app/components/user-profile/UserRoomProfile.tsx b/src/app/components/user-profile/UserRoomProfile.tsx
index 02a95ca0..ff301764 100644
--- a/src/app/components/user-profile/UserRoomProfile.tsx
+++ b/src/app/components/user-profile/UserRoomProfile.tsx
@@ -53,11 +53,7 @@ type UserRoomProfileProps = {
   avatarExpanded?: boolean;
 };
 
-export function UserRoomProfile({
-  userId,
-  onAvatarClick,
-  avatarExpanded,
-}: UserRoomProfileProps) {
+export function UserRoomProfile({ userId, onAvatarClick, avatarExpanded }: UserRoomProfileProps) {
   const mx = useMatrixClient();
   const useAuthentication = useMediaAuthentication();
   const navigate = useNavigate();
@@ -86,7 +82,23 @@ export function UserRoomProfile({
 
   const displayName = getMemberDisplayName(room, userId);
   const avatarMxc = getMemberAvatarMxc(room, userId);
-  const avatarUrl = (avatarMxc && mxcUrlToHttp(mx, avatarMxc, useAuthentication)) ?? undefined;
+  // The collapsed HeroAvatar renders at 96px CSS (user-profile/styles.css.ts).
+  // A `crop` thumbnail can't fix retina sharpness here: Synapse only
+  // pre-generates 32px and 96px CROP thumbnails by default, so any `crop`
+  // request > 96 just returns the 96px one — upscaled and pixelated on a 2–3×
+  // display. `scale` thumbnails go up to 320/640/800, so we request a 320 scale:
+  // sharp on retina yet ~10× smaller than the full-resolution original (which
+  // the SDK returns when no dimensions are passed, and which made the hero
+  // visibly progressive-load on open). `UserAvatar` forces `object-fit: cover`,
+  // so a non-square scale thumbnail still fills the circle. The full-res
+  // original is reserved for the expanded tile + tap-to-zoom fullview below.
+  const avatarUrl =
+    (avatarMxc && mxcUrlToHttp(mx, avatarMxc, useAuthentication, 320, 320, 'scale')) ?? undefined;
+  // Full-resolution original for the desktop side-pane expanded (~340px) tile —
+  // a 96px thumbnail would upscale and pixelate when blown up. Only fetched
+  // when the avatar is expanded (UserHero swaps to this src then).
+  const avatarUrlExpanded =
+    (avatarMxc && mxcUrlToHttp(mx, avatarMxc, useAuthentication)) ?? undefined;
 
   // Pass the raw SDK presence through. `UserHero` already guards on
   // `lastActiveTs > 0` before formatting the last-seen line, so the
@@ -144,6 +156,7 @@ export function UserRoomProfile({
         userId={userId}
         displayName={displayName}
         avatarUrl={avatarUrl}
+        avatarUrlExpanded={avatarUrlExpanded}
         presence={presence}
         encrypted={encrypted}
         onAvatarClick={onAvatarClick}