Load profile pics from CDN pubkey path before kind 0

Try cdn.zapstore.dev/p/{pubkey}.webp first (iconsm when tiny), then fall back to the kind-0 picture URL on error.

lib/utils/image_url.dart

@@ -21,3 +21,15 @@ String? getCdnImageUrl(String? imageUrl, CdnImageVariant variant) {
   params['class'] = variant.name;
   return uri.replace(queryParameters: params).toString();
 }
+
+/// Zapstore CDN profile picture for a hex pubkey (256px by default).
+///
+/// For tiny avatars, pass [tiny] to request `class=iconsm`.
+String? getProfileCdnUrl(String? pubkey, {bool tiny = false}) {
+  if (pubkey == null || pubkey.isEmpty) return null;
+  if (!RegExp(r'^[0-9a-fA-F]{64}$').hasMatch(pubkey)) return null;
+
+  final url = 'https://$_cdnHost/p/${pubkey.toLowerCase()}.webp';
+  if (!tiny) return url;
+  return getCdnImageUrl(url, CdnImageVariant.iconsm);
+}

lib/widgets/common/profile_avatar.dart

@@ -5,13 +5,14 @@ import 'package:zapstore/utils/image_url.dart';
 import 'package:zapstore/utils/url_utils.dart';
 import '../../theme.dart';
 
-class ProfileAvatar extends StatelessWidget {
+class ProfileAvatar extends StatefulWidget {
   final Profile? profile;
   final double radius;
   final List<Color>? borderColors;
 
   /// When provided, shows a signed-in placeholder (account_circle)
   /// instead of the generic person icon used for signed-out state.
+  /// Also used for the CDN profile picture path when [profile] is null.
   final String? pubkey;
 
   const ProfileAvatar({
@@ -22,12 +23,53 @@ class ProfileAvatar extends StatelessWidget {
     this.pubkey,
   });
 
+  @override
+  State<ProfileAvatar> createState() => _ProfileAvatarState();
+}
+
+class _ProfileAvatarState extends State<ProfileAvatar> {
+  /// When true, skip the CDN pubkey URL and use kind-0 picture instead.
+  bool _useKind0Fallback = false;
+
+  bool get _tiny => widget.radius < 24;
+
+  String? get _resolvedPubkey => widget.profile?.pubkey ?? widget.pubkey;
+
+  String? get _cdnUrl => getProfileCdnUrl(_resolvedPubkey, tiny: _tiny);
+
+  String? get _kind0Url => getCdnImageUrl(
+        sanitizeHttpUrl(widget.profile?.pictureUrl),
+        _tiny ? CdnImageVariant.iconsm : CdnImageVariant.icon,
+      );
+
+  String? get _imageUrl {
+    if (!_useKind0Fallback) {
+      final cdn = _cdnUrl;
+      if (cdn != null) return cdn;
+    }
+    return _kind0Url;
+  }
+
+  @override
+  void didUpdateWidget(covariant ProfileAvatar oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    final pubkeyChanged =
+        (oldWidget.profile?.pubkey ?? oldWidget.pubkey) != _resolvedPubkey;
+    final pictureChanged =
+        oldWidget.profile?.pictureUrl != widget.profile?.pictureUrl;
+    final radiusCrossedTiny =
+        (oldWidget.radius < 24) != _tiny;
+    if (pubkeyChanged || pictureChanged || radiusCrossedTiny) {
+      _useKind0Fallback = false;
+    }
+  }
+
   Widget _buildPlaceholder(BuildContext context) {
     // Use different icon for signed-in vs signed-out state
-    final isSignedIn = pubkey != null;
+    final isSignedIn = widget.pubkey != null || widget.profile != null;
     return Container(
-      width: radius * 2,
-      height: radius * 2,
+      width: widget.radius * 2,
+      height: widget.radius * 2,
       color: const Color(0xFF1A1A1A),
       child: Center(
         child: Icon(
@@ -35,40 +77,50 @@ class ProfileAvatar extends StatelessWidget {
           color: isSignedIn
               ? Theme.of(context).colorScheme.primary.withValues(alpha: 0.6)
               : Theme.of(context).colorScheme.onSurface.withValues(alpha: 0.3),
-          size: isSignedIn ? radius * 1.8 : radius * 0.9,
+          size: isSignedIn ? widget.radius * 1.8 : widget.radius * 0.9,
         ),
       ),
     );
   }
 
+  void _onImageError(String failedUrl) {
+    if (_useKind0Fallback) return;
+    final kind0 = _kind0Url;
+    if (kind0 == null || kind0 == failedUrl) return;
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (mounted) setState(() => _useKind0Fallback = true);
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
-    final pictureUrl = getCdnImageUrl(
-      sanitizeHttpUrl(profile?.pictureUrl),
-      radius < 24 ? CdnImageVariant.iconsm : CdnImageVariant.icon,
-    );
+    final pictureUrl = _imageUrl;
 
     Widget avatar = ClipOval(
       child: pictureUrl != null
           ? CachedNetworkImage(
+              key: ValueKey(pictureUrl),
               imageUrl: pictureUrl,
               fit: BoxFit.cover,
-              width: radius * 2,
-              height: radius * 2,
+              width: widget.radius * 2,
+              height: widget.radius * 2,
               fadeInDuration: const Duration(milliseconds: 500),
               fadeOutDuration: const Duration(milliseconds: 200),
               placeholder: (context, url) => _buildPlaceholder(context),
-              errorWidget: (context, url, error) => _buildPlaceholder(context),
+              errorWidget: (context, url, error) {
+                _onImageError(url);
+                return _buildPlaceholder(context);
+              },
             )
           : _buildPlaceholder(context),
     );
 
-    if (borderColors != null) {
+    if (widget.borderColors != null) {
       return Container(
         padding: const EdgeInsets.all(3),
         decoration: BoxDecoration(
           shape: BoxShape.circle,
-          gradient: LinearGradient(colors: borderColors!),
+          gradient: LinearGradient(colors: widget.borderColors!),
         ),
         child: Container(
           decoration: BoxDecoration(

lib/widgets/profile_header.dart

@@ -32,7 +32,7 @@ class ProfileHeader extends StatelessWidget {
       child: Column(
         children: [
           // Profile avatar (handles null profile with fallback)
-          ProfileAvatar(profile: profile, radius: radius),
+          ProfileAvatar(profile: profile, pubkey: pubkey, radius: radius),
           const SizedBox(height: 16),
 
           // Display name with loading state

test/utils/image_url_test.dart

@@ -43,4 +43,30 @@ void main() {
       expect(getCdnImageUrl('', CdnImageVariant.icon), '');
     });
   });
+
+  group('getProfileCdnUrl', () {
+    const pubkey =
+        '3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c1eb8ce57016d6d';
+
+    test('builds the 256px CDN profile URL', () {
+      expect(
+        getProfileCdnUrl(pubkey),
+        'https://cdn.zapstore.dev/p/$pubkey.webp',
+      );
+    });
+
+    test('adds iconsm for tiny avatars', () {
+      expect(
+        getProfileCdnUrl(pubkey, tiny: true),
+        'https://cdn.zapstore.dev/p/$pubkey.webp?class=iconsm',
+      );
+    });
+
+    test('rejects non-hex and empty pubkeys', () {
+      expect(getProfileCdnUrl(null), isNull);
+      expect(getProfileCdnUrl(''), isNull);
+      expect(getProfileCdnUrl('npub1abc'), isNull);
+      expect(getProfileCdnUrl('not-a-key'), isNull);
+    });
+  });
 }