Improve handling of images.

examples/travel_app/integration_test/app_test.dart

@@ -74,16 +74,16 @@ const Map<String, Object> _baliResponse = {
               'TravelCarousel': {
                 'items': [
                   {
-                    'imageChild': 'bali_memorial_image',
+                    'imageChildId': 'bali_memorial_image',
                     'title': 'Cultural Immersion',
                   },
                   {
-                    'imageChild': 'nyepi_festival_image',
+                    'imageChildId': 'nyepi_festival_image',
                     'title': 'Festivals and Traditions',
                   },
                   {
                     'title': 'Beach Relaxation',
-                    'imageChild': 'kata_noi_beach_image',
+                    'imageChildId': 'kata_noi_beach_image',
                   },
                 ],
               },
@@ -94,7 +94,7 @@ const Map<String, Object> _baliResponse = {
             'widget': {
               'Image': {
                 'fit': 'cover',
-                'assetName': 'assets/travel_images/bali_memorial.jpg',
+                'location': 'assets/travel_images/bali_memorial.jpg',
               },
             },
           },
@@ -103,19 +103,19 @@ const Map<String, Object> _baliResponse = {
             'widget': {
               'Image': {
                 'fit': 'cover',
-                'assetName': 'assets/travel_images/nyepi_festival_bali.jpg',
+                'location': 'assets/travel_images/nyepi_festival_bali.jpg',
               },
             },
           },
           {
+            'id': 'kata_noi_beach_image',
             'widget': {
               'Image': {
-                'assetName':
-                    'assets/travel_images/kata_noi_beach_phuket_thailand.jpg',
                 'fit': 'cover',
+                'location':
+                    'assets/travel_images/kata_noi_beach_phuket_thailand.jpg',
               },
             },
-            'id': 'kata_noi_beach_image',
           },
           {
             'widget': {

examples/travel_app/lib/src/catalog/travel_carousel.dart

@@ -290,13 +290,13 @@ JsonMap _hotelExample() {
       {
         'id': 'image_1',
         'widget': {
-          'Image': {'fit': 'cover', 'assetName': hotel1.images[0]},
+          'Image': {'fit': 'cover', 'location': hotel1.images[0]},
         },
       },
       {
         'id': 'image_2',
         'widget': {
-          'Image': {'fit': 'cover', 'assetName': hotel2.images[0]},
+          'Image': {'fit': 'cover', 'location': hotel2.images[0]},
         },
       },
     ],
@@ -355,7 +355,7 @@ JsonMap _inspirationExample() => {
       'widget': {
         'Image': {
           'fit': 'cover',
-          'assetName': 'assets/travel_images/santorini_panorama.jpg',
+          'location': 'assets/travel_images/santorini_panorama.jpg',
         },
       },
     },
@@ -364,7 +364,7 @@ JsonMap _inspirationExample() => {
       'widget': {
         'Image': {
           'fit': 'cover',
-          'assetName':
+          'location':
               'assets/travel_images/akrotiri_spring_fresco_santorini.jpg',
         },
       },
@@ -373,7 +373,7 @@ JsonMap _inspirationExample() => {
       'id': 'santorini_caldera_image',
       'widget': {
         'Image': {
-          'assetName': 'assets/travel_images/santorini_from_space.jpg',
+          'location': 'assets/travel_images/santorini_from_space.jpg',
           'fit': 'cover',
         },
       },
@@ -382,7 +382,7 @@ JsonMap _inspirationExample() => {
       'widget': {
         'Image': {
           'fit': 'cover',
-          'assetName':
+          'location':
               'assets/travel_images/saffron_gatherers_fresco_santorini.jpg',
         },
       },

examples/travel_app/lib/src/tools/booking/booking_service.dart

@@ -58,7 +58,7 @@ class BookingService {
             location: 'Mountain View, CA',
             pricePerNight: 250.0,
             listingSelectionId: _generateListingSelectionId(),
-            images: ['assets/booking_service/flutter_hotel.jpeg'],
+            images: ['assets/booking_service/flutter_hotel.png'],
             search: search,
           ),
         ),

examples/travel_app/lib/src/travel_planner_page.dart

@@ -435,8 +435,7 @@ ${_imagesJson ?? ''}
 list that might be tangentially relevant. DO NOT USE ANY IMAGES NOT IN THE LIST.
 It is fine if the image is irrelevant, as long as it is from the list.
 
-- Use assetName for images from the list only - NEVER use `url` and reference
-images from wikipedia or other sites.
+- Image location always should be an asset path (e.g. assets/...).
 
 # Example
 
@@ -483,7 +482,7 @@ contain the other widgets.
         "id": "mexico_city_image",
         "widget": {
           "Image": {
-            "assetName": "assets/travel_images/mexico_city.jpg"
+            "location": "assets/travel_images/mexico_city.jpg"
           }
         }
       },
@@ -516,7 +515,7 @@ contain the other widgets.
         "id": "day1_image",
         "widget": {
           "Image": {
-            "assetName": "assets/travel_images/mexico_city.jpg"
+            "location": "assets/travel_images/mexico_city.jpg"
           }
         }
       },

packages/flutter_genui/lib/src/catalog/core_widgets/image.dart

@@ -10,15 +10,9 @@ import '../../primitives/simple_items.dart';
 
 final _schema = S.object(
   properties: {
-    'url': S.string(
+    'location': S.string(
       description:
-          'The URL of the image to display. Only one '
-          'of url or assetName may be specified.',
-    ),
-    'assetName': S.string(
-      description:
-          'The name of the asset to display. Only '
-          'one of assetName or url may be specified.',
+          'Asset path (e.g. assets/...) or network URL (e.g. https://...)',
     ),
     'fit': S.string(
       description: 'How the image should be inscribed into the box.',
@@ -28,11 +22,10 @@ final _schema = S.object(
 );
 
 extension type _ImageData.fromMap(JsonMap _json) {
-  factory _ImageData({String? url, String? assetName, String? fit}) =>
-      _ImageData.fromMap({'url': url, 'assetName': assetName, 'fit': fit});
+  factory _ImageData({required String location, String? fit}) =>
+      _ImageData.fromMap({'location': location, 'fit': fit});
 
-  String? get url => _json['url'] as String?;
-  String? get assetName => _json['assetName'] as String?;
+  String get location => _json['location'] as String;
   BoxFit? get fit => _json['fit'] != null
       ? BoxFit.values.firstWhere((e) => e.name == _json['fit'] as String)
       : null;
@@ -52,25 +45,13 @@ final image = CatalogItem(
       }) {
         final imageData = _ImageData.fromMap(data as JsonMap);
 
-        final url = imageData.url;
-        final assetName = imageData.assetName;
-
-        if ((url == null) == (assetName == null)) {
-          throw Exception(
-            'Image widget must have either a url or an assetName, '
-            'but not both. '
-            'Details: $imageData',
-          );
-        }
+        final location = imageData.location;
+        final fit = imageData.fit;
 
-        if (url != null) {
-          return Image.network(url, fit: imageData.fit);
+        if (location.startsWith('assets/')) {
+          return Image.asset(location, fit: fit);
+        } else {
+          return Image.network(location, fit: fit);
         }
-
-        if (assetName != null) {
-          return Image.asset(assetName, fit: imageData.fit);
-        }
-
-        return const SizedBox();
       },
 );

packages/flutter_genui/test/image_test.dart

@@ -19,7 +19,7 @@ void main() {
             builder: (context) => Scaffold(
               body: image.widgetBuilder(
                 data: {
-                  'url':
+                  'location':
                       'https://www.google.com/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png',
                 },
                 id: 'test_image',