diff --git a/web/src/features/groups/GroupAdminModal.tsx b/web/src/features/groups/GroupAdminModal.tsx
index 53aab35a..077160d6 100644
--- a/web/src/features/groups/GroupAdminModal.tsx
+++ b/web/src/features/groups/GroupAdminModal.tsx
@@ -5,6 +5,7 @@ import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
 import { Icon } from '@/app/Icon';
 import { Toast } from '@/app/Toast';
 import { JoinRequestsModal } from '@/features/groups/JoinRequestsModal';
+import { privateChatOption, privateChatOptions } from '@/features/groups/group-settings';
 import {
   addGroupAdmins,
   getAllGroupMembers,
@@ -184,11 +185,8 @@ export function GroupAdminModal({ topicId, onClose }: GroupAdminModalProps) {
           <div className="flex items-center justify-between border-b border-border-list-item py-3.5">
             <span className="text-text-body">成员私聊权限</span>
             <SegmentedControl
-              value={govQuery.data?.member_private_chat ? 'all' : 'friends'}
-              options={[
-                { value: 'all', label: '允许' },
-                { value: 'friends', label: '仅好友' },
-              ]}
+              value={privateChatOption(!!govQuery.data?.member_private_chat)}
+              options={privateChatOptions}
               onChange={(v) => setGov({ member_private_chat: v === 'all' })}
               disabled={!govQuery.data || govMutation.isPending || govQuery.data?.member_private_chat_editable === false}
             />
diff --git a/web/src/features/groups/GroupDetailColumn.tsx b/web/src/features/groups/GroupDetailColumn.tsx
index 4ab6b416..2dd72349 100644
--- a/web/src/features/groups/GroupDetailColumn.tsx
+++ b/web/src/features/groups/GroupDetailColumn.tsx
@@ -11,6 +11,7 @@ import { GroupAdminModal } from '@/features/groups/GroupAdminModal';
 import { GroupAnnouncementModal } from '@/features/groups/GroupAnnouncementModal';
 import { GroupFilesModal } from '@/features/groups/GroupFilesModal';
 import { GroupMembersModal } from '@/features/groups/GroupMembersModal';
+import { canEditGroupAvatar, groupAvatarError } from '@/features/groups/group-settings';
 import {
   canRemoveMember,
   disbandGroup,
@@ -28,6 +29,7 @@ import {
   type GroupSettings,
 } from '@/lib/api/groups';
 import type { MediaType } from '@/lib/api/messages';
+import { uploadFile } from '@/lib/api/upload';
 import { MAX_TITLE_LENGTH } from '@/lib/config';
 import { useTinode } from '@/lib/tinode/hooks';
 import { forgetTopic } from '@/lib/tinode/topics';
@@ -129,6 +131,10 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
   const myRole = settingsQuery.data?.my_role;
   const isOwner = myRole === 'owner';
   const isAdmin = myRole === 'admin' || isOwner;
+  const canEditAvatar = canEditGroupAvatar(
+    settingsQuery.data?.permissions?.can_edit_profile ?? groupQuery.data?.permissions?.can_edit_profile,
+    myRole,
+  );
   // GroupAdminModal's "邀请入群权限" governance toggle (所有成员/仅管理员) was added without ever
   // being read anywhere -- every real gate on the invite affordance stayed hardcoded to
   // owner/admin-only, so flipping that toggle to "所有成员" had zero effect on what a plain member
@@ -186,6 +192,30 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
     onError: (err) => showError(err, '群名保存失败'),
   });
 
+  const avatarMutation = useMutation({
+    mutationFn: async ({ file, topic, version }: { file: File; topic: string; version: number }) => {
+      const uploaded = await uploadFile(file, undefined, 'group_avatar');
+      return { ...(await updateGroup(topic, { avatar_file_id: uploaded.file_id, version })), avatar_file_id: uploaded.file_id };
+    },
+    onSuccess: (data, { topic }) => {
+      queryClient.setQueryData(['group', topic], (prev: GroupProfile | undefined) => (prev ? { ...prev, ...data } : data));
+      queryClient.invalidateQueries({ queryKey: ['group', topic] });
+      queryClient.invalidateQueries({ queryKey: ['group-settings', topic] });
+      queryClient.invalidateQueries({ queryKey: ['groups', 'all'] });
+    },
+    onError: (err) => showError(err, '群头像修改失败'),
+  });
+  const avatarUploading = avatarMutation.isPending && avatarMutation.variables?.topic === topicId;
+
+  const handlePickAvatar = (e: React.ChangeEvent<HTMLInputElement>) => {
+    const file = e.target.files?.[0];
+    e.target.value = '';
+    if (!file) return;
+    const error = groupAvatarError(file);
+    if (error) setErrorToast(error);
+    else if (groupQuery.data) avatarMutation.mutate({ file, topic: topicId, version: groupQuery.data.version });
+  };
+
   // Both mutations call forgetTopic() the instant their own REST call succeeds, rather than waiting
   // on the async native/`group.dissolved` gone-signal that normally follows a group actually going
   // away -- real, user-reported bugs fixed by this: (1) the chat list kept showing a broken stale
@@ -304,12 +334,20 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
         <div className="bg-white md:contents">
           <div className="flex flex-col gap-2 px-4 py-4 md:border-b md:border-border-list-item md:px-5">
             <div className="flex items-center gap-3">
-              <Avatar
-                id={topicId}
-                name={groupQuery.data?.name || peerName}
-                avatarFileId={groupQuery.data?.avatar_file_id}
-                className="h-13 w-13 flex-none rounded-xl text-xl"
-              />
+              <div className="relative flex-none">
+                <Avatar
+                  id={topicId}
+                  name={groupQuery.data?.name || peerName}
+                  avatarFileId={groupQuery.data?.avatar_file_id}
+                  className="h-13 w-13 rounded-xl text-xl"
+                />
+                {canEditAvatar && groupQuery.data ? (
+                  <label className="absolute -bottom-1 -right-1 grid h-6 w-6 cursor-pointer place-items-center rounded-full bg-white text-text-tertiary-1 shadow-btn-sm" aria-label="修改群头像">
+                    {avatarUploading ? <span className="text-[9px]">上传中</span> : <Icon name="photo_camera" className="text-[14px]" />}
+                    <input type="file" accept="image/*" onChange={handlePickAvatar} disabled={avatarUploading || nameMutation.isPending} className="hidden" />
+                  </label>
+                ) : null}
+              </div>
               <div className="flex min-w-0 flex-1 flex-col">
                 {nameEditing ? (
                   <div className="flex items-center gap-2">
@@ -317,13 +355,13 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
                       autoFocus
                       value={nameDraft}
                       onChange={(e) => setNameDraft(e.target.value.slice(0, MAX_TITLE_LENGTH))}
-                      onKeyDown={(e) => e.key === 'Enter' && nameDraft.trim() && nameMutation.mutate(nameDraft.trim())}
+                      onKeyDown={(e) => e.key === 'Enter' && nameDraft.trim() && !avatarUploading && nameMutation.mutate(nameDraft.trim())}
                       className="min-w-0 flex-1 rounded-md bg-surface-input px-2 py-1 text-sm outline-none"
                     />
                     <button
                       type="button"
                       onClick={() => nameDraft.trim() && nameMutation.mutate(nameDraft.trim())}
-                      disabled={!nameDraft.trim() || nameMutation.isPending}
+                      disabled={!nameDraft.trim() || nameMutation.isPending || avatarUploading}
                       className="flex-none text-sm text-accent disabled:opacity-40"
                     >
                       保存
diff --git a/web/src/features/groups/group-settings.ts b/web/src/features/groups/group-settings.ts
new file mode 100644
index 00000000..af9b9efd
--- /dev/null
+++ b/web/src/features/groups/group-settings.ts
@@ -0,0 +1,17 @@
+export const privateChatOptions: { value: 'all' | 'friends'; label: string }[] = [
+  { value: 'all', label: '全员' },
+  { value: 'friends', label: '好友添加' },
+];
+
+export function privateChatOption(enabled: boolean): 'all' | 'friends' {
+  return enabled ? 'all' : 'friends';
+}
+
+export function canEditGroupAvatar(permission: boolean | undefined, role: 'owner' | 'admin' | 'member' | undefined): boolean {
+  return permission ?? (role === 'owner' || role === 'admin');
+}
+
+export function groupAvatarError(file: Pick<File, 'type' | 'size'>): string | null {
+  if (!file.type.startsWith('image/')) return '请选择图片文件';
+  return file.size > 5 * 1024 * 1024 ? '图片大小不能超过 5MB' : null;
+}
diff --git a/web/tests/group-settings.test.ts b/web/tests/group-settings.test.ts
new file mode 100644
index 00000000..f145a8b5
--- /dev/null
+++ b/web/tests/group-settings.test.ts
@@ -0,0 +1,28 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { canEditGroupAvatar, groupAvatarError, privateChatOption, privateChatOptions } from '../src/features/groups/group-settings.ts';
+
+test('member private chat labels keep the existing boolean mapping', () => {
+  assert.deepEqual(privateChatOptions, [
+    { value: 'all', label: '全员' },
+    { value: 'friends', label: '好友添加' },
+  ]);
+  assert.equal(privateChatOption(true), 'all');
+  assert.equal(privateChatOption(false), 'friends');
+});
+
+test('server profile permission overrides role, with role fallback only when absent', () => {
+  assert.equal(canEditGroupAvatar(true, 'member'), true);
+  assert.equal(canEditGroupAvatar(false, 'owner'), false);
+  assert.equal(canEditGroupAvatar(false, 'admin'), false);
+  assert.equal(canEditGroupAvatar(undefined, 'owner'), true);
+  assert.equal(canEditGroupAvatar(undefined, 'admin'), true);
+  assert.equal(canEditGroupAvatar(undefined, 'member'), false);
+});
+
+test('group avatar accepts images up to 5MB and rejects other files', () => {
+  assert.equal(groupAvatarError({ type: 'image/png', size: 5 * 1024 * 1024 }), null);
+  assert.equal(groupAvatarError({ type: 'text/plain', size: 10 }), '请选择图片文件');
+  assert.equal(groupAvatarError({ type: 'image/jpeg', size: 5 * 1024 * 1024 + 1 }), '图片大小不能超过 5MB');
+});