Add screenshot for mobile-screens, add frames delay section

Author: markushi

docs/product/insights/mobile/mobile-screens/img/mobile-screens.png

@@ -4,6 +4,10 @@ sidebar_order: 0
 description: "Track the UI performance of your screens."
 ---
 
+The mobile screens insights module provides a high-level overview of the performance of your screens, and allows you to drill down into the performance metrics of individual screens.
+
+![The mobile screens insights module.](./img/mobile-screens.png)
+
 ## App Start
 
 App start metrics track how long your mobile application takes to launch. For this, Sentry measures _cold starts_ and _warm starts_.
@@ -30,6 +34,8 @@ To track the responsiveness of the user interface, Sentry measures _slow frames_
 
 For Apple, the frame rate can be higher, especially as 120 fps displays are becoming more popular. For these apps, Sentry detects the frame rate and adjusts the slow frame calculation accordingly.
 
+On the mobile screens insights page, you can see a slow and frozen frame rate, indicating the percentage of frames that are slow or frozen during the lifetime of the transaction.
+
 In the example below, the detail view of the transaction displays the slow, frozen, and total frames in an iOS application:
 
 ![The event detail of a transaction with slow and frozen frames measurements.](./img/slow-frozen-frames.png)
@@ -41,6 +47,15 @@ You can track slow and frozen frames for:
 - [iOS](/platforms/apple/guides/ios/tracing/instrumentation/automatic-instrumentation/#slow-and-frozen-frames)
 - [React Native](/platforms/react-native/tracing/instrumentation/automatic-instrumentation/#slow-and-frozen-frames)
 
+## Frames Delay
+
+Frames Delay is the user-perceived delayed duration of rendered frames. For example, at a refresh rate of 60fps, if a single frame render takes 20ms, the frame delay is 4ms (20ms - 16ms = 4ms).
+
+You can track frames delay on the following platforms:
+- [Android](platforms/android/tracing/instrumentation/perf-v2/#frames-delay)
+- [Flutter](/platforms/flutter/integrations/slow-and-frozen-frames-instrumentation/)
+- [iOS, as part of slow and frozen frames](/platforms/apple/guides/ios/tracing/instrumentation/automatic-instrumentation/#slow-and-frozen-frames)
+
 ## Time to Initial Display and Time to Full Display
 
 To track how long it takes your application to produce its first frame and then how long it takes to produce its first frame with all the content, Sentry measures time to initial display and time to full display, respectively.