Fixed warning I got running your code with react 0.55.4
08-27 17:54:49.977 8562 10093 W ReactNativeJS: Warning: Failed child context type: Invalid child context virtualizedCell.cellKey of type number supplied to CellRenderer, expected string.
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in CellRenderer (at VirtualizedList.js:670)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in AndroidHorizontalScrollContentView (at ScrollView.js:791)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in AndroidHorizontalScrollView (at ScrollView.js:887)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in ScrollView (at VirtualizedList.js:1024)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in VirtualizedList (at FlatList.js:644)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in FlatList (at index.js:318)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at index.js:314)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in ViewPager (at index.js:275)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in ImageGallery (at index.js:43)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in ShowImage (created by Connect(ShowImage))
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Connect(ShowImage) (at SceneView.js:9)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in SceneView (at StackViewLayout.js:505)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at StackViewLayout.js:504)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at StackViewLayout.js:503)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at createAnimatedComponent.js:154)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in AnimatedComponent (at StackViewCard.js:12)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Card (at createPointerEventsContainer.js:28)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Container (at StackViewLayout.js:554)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at StackViewLayout.js:462)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at StackViewLayout.js:461)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in StackViewLayout (at withOrientation.js:30)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in withOrientation (at StackView.js:63)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at Transitioner.js:169)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Transitioner (at StackView.js:21)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in StackView (at createNavigator.js:59)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Navigator (at createKeyboardAwareNavigator.js:11)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in KeyboardAwareNavigator (at createNavigationContainer.js:376)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in NavigationContainer (at TimeThreadApp.js:41)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in TimeThreadApp (created by Connect(TimeThreadApp))
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Connect(TimeThreadApp) (at App.js:31)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Provider (at App.js:30)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at Root.js:13)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Root (at connectStyle.js:384)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in Styled(Root) (at App.js:29)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in App (at renderApplication.js:33)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at AppContainer.js:102)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in RCTView (at View.js:60)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in View (at AppContainer.js:122)
08-27 17:54:49.977 8562 10093 W ReactNativeJS: in AppContainer (at renderApplication.js:32)
Fixed warning I got running your code with react 0.55.4