[fix] Image 'source' prop update when missing in initial render

Close #811

packages/react-native-web/src/exports/Image/__tests__/index-test.js

@@ -180,6 +180,20 @@ describe('components/Image', () => {
           .attr('src')
       ).toBe(uriTwo);
     });
+
+    test('is correctly updated when missing in initial render', () => {
+      jest.useFakeTimers();
+      const uri = 'https://testing.com/img.jpg';
+      const component = mount(<Image />);
+      component.setProps({ source: { uri } });
+      jest.runOnlyPendingTimers();
+      expect(
+        component
+          .render()
+          .find('img')
+          .attr('src')
+      ).toBe(uri);
+    });
   });
 
   describe('prop "style"', () => {

packages/react-native-web/src/exports/Image/index.js

@@ -168,8 +168,8 @@ class Image extends Component<*, State> {
     if (uri !== nextUri) {
       ImageUriCache.remove(uri);
       const isPreviouslyLoaded = ImageUriCache.has(nextUri);
-      isPreviouslyLoaded && ImageUriCache.add(uri);
-      this._updateImageState(getImageState(uri, isPreviouslyLoaded));
+      isPreviouslyLoaded && ImageUriCache.add(nextUri);
+      this._updateImageState(getImageState(nextUri, isPreviouslyLoaded));
     }
   }