Add screenshots, edit README (#319)



Former-commit-id: 2939c3bae3a6daf4ea4095366a5293e561acc903
diff --git a/README.md b/README.md
index 06f8e33..0118479 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,16 @@
 # Flutter Gallery
 
 Flutter Gallery is a resource to help developers evaluate and use Flutter.
-It is a collection of material design widgets, behaviors, and vignettes
+It is a collection of Material Design & Cupertino widgets, behaviors, and vignettes
 implemented with Flutter. We often get asked how one can see Flutter in action,
 and this gallery demonstrates what Flutter provides and how it behaves in the
 wild.
 
+![Flutter Gallery](https://user-images.githubusercontent.com/6655696/73928238-0d7fcc80-48d3-11ea-8a7e-ea7dc5d6e713.png)
+
 ## Supported Platforms
 
-The Flutter Gallery application has been built to support multiple platforms.
+Flutter Gallery has been built to support multiple platforms.
 This includes:
 
 - Android
@@ -31,7 +33,7 @@
 
 Additionally, the UI adapts between mobile and desktop layouts regardless of the
 platform it runs on. This is determined based on window size as outlined in
-[adaptive.dart](gallery/lib/layout/adaptive.dart).
+[adaptive.dart](lib/layout/adaptive.dart).
 
 ## To include a new splash animation
 
@@ -45,7 +47,7 @@
    current largest number in the repository.
 
 3. Update the map `_effectDurations` in
-   [splash.dart](gallery/lib/pages/splash.dart) to include the number of the
+   [splash.dart](lib/pages/splash.dart) to include the number of the
    new `.gif` as well as its estimated duration. The duration is used to
    determine how long to display the splash animation at launch.
 
@@ -58,14 +60,14 @@
 flutter pub get
 ```
 
-To generate localized strings (see separate [README](gallery/lib/l10n/README.md)
+To generate localized strings (see separate [README](lib/l10n/README.md)
 for more details):
 
 ```
 flutter pub run grinder l10n
 ```
 
-To generate code segments (see separate [README](gallery/tool/codeviewer_cli/README.md) for
+To generate code segments (see separate [README](tool/codeviewer_cli/README.md) for
 more details):
 ```
 flutter pub run grinder update-code-segments
diff --git a/screenshots.md b/screenshots.md
new file mode 100644
index 0000000..ea274d4
--- /dev/null
+++ b/screenshots.md
@@ -0,0 +1,18 @@
+# Screenshots
+<img width="1648" alt="macOS-dark" src="https://user-images.githubusercontent.com/6655696/73928206-fe991a00-48d2-11ea-837b-488c6f584875.png">
+<img width="1648" alt="macOS-light" src="https://user-images.githubusercontent.com/6655696/73928211-ffca4700-48d2-11ea-93f4-c1f368bfa6c7.png">
+<img width="540" alt="iPhone-dark" src="https://user-images.githubusercontent.com/6655696/73928221-035dce00-48d3-11ea-8906-1bf33629e527.png">
+<img width="540" alt="iPhone-light" src="https://user-images.githubusercontent.com/6655696/73928224-048efb00-48d3-11ea-8869-7da35d727cf1.png">
+<img width="552" alt="pixel-dark" src="https://user-images.githubusercontent.com/6655696/73928225-0658be80-48d3-11ea-9c44-4ae3c3f8b26e.png">
+<img width="553" alt="pixel-light" src="https://user-images.githubusercontent.com/6655696/73928228-0789eb80-48d3-11ea-9bf5-d82618f55327.png">
+<img width="1373" alt="iPad-dark" src="https://user-images.githubusercontent.com/6655696/73928238-0d7fcc80-48d3-11ea-8a7e-ea7dc5d6e713.png">
+<img width="1373" alt="iPad-light" src="https://user-images.githubusercontent.com/6655696/73928252-12448080-48d3-11ea-8c42-ce612f2b4b1f.png">
+<img width="1373" alt="studies-shrine" src="https://user-images.githubusercontent.com/6655696/73928288-225c6000-48d3-11ea-89d0-34914866533e.png">
+<img width="1373" alt="studies-rally" src="https://user-images.githubusercontent.com/6655696/73928289-24beba00-48d3-11ea-9b4f-c352e314a605.png">
+<img width="1373" alt="studies-crane" src="https://user-images.githubusercontent.com/6655696/73928291-25efe700-48d3-11ea-8bd4-14125d32e0a4.png">
+<img width="1373" alt="studies-fortnightly" src="https://user-images.githubusercontent.com/6655696/73928295-27211400-48d3-11ea-86d1-fcda50ab94e7.png">
+<img width="1373" alt="studies-starter" src="https://user-images.githubusercontent.com/6655696/73928297-28524100-48d3-11ea-9f4d-6c4e26e08c6d.png">
+<img width="1373" alt="demos-textfields" src="https://user-images.githubusercontent.com/6655696/73928302-2ab49b00-48d3-11ea-93fb-e9a358010aa5.png">
+<img width="1373" alt="demos-color" src="https://user-images.githubusercontent.com/6655696/73928303-2be5c800-48d3-11ea-919f-e2abf6a067e2.png">
+<img width="1373" alt="demos-typography" src="https://user-images.githubusercontent.com/6655696/73928306-2d16f500-48d3-11ea-9be4-bad3d26508c0.png">
+<img width="1373" alt="settings" src="https://user-images.githubusercontent.com/6655696/73928313-2e482200-48d3-11ea-9cae-4031209041d2.png">