The proper solution to get the result you want is to add a flexBasis to the TabView like:

<TabView 
  style={{ flexBasis: 0 }}
  // rest of the code
/> ​

Why? The TabView has a default style of flex: 1, overflow: 'hidden' (see source code) causing it to expanded to the size of its biggest child. The flexBasis prevents this and makes sure the tabview get the correct height.

Resource: This is a nice article about flexBasis vs width/height: https://mastery.games/post/the-difference-between-width-and-flex-basis/

Debugging styling in React-Native doesn't have the best developer experience. There are some things you can use to help you with debugging styling:

• RN inspector: As Berci mentioned, React native has a dev menu where you can select "show inspector" that kinda acts like "inspect element" in a browser. It is a good tool to debug elements you can see, it also helps with debugging input/tab events.

• Color: Most often I just use old fashioned colored borders & background to get a clear view of where elements are & their size/overlaps.

• Comments & Simplify: Feel free to comment out components you're not interested in and replace complex components/views like ScrollCards with just a simple colored view. This can help prevent multiple behaviours from influencing the thing you're trying to debug

• Browser inspect & React devtools: If you happen to run your RN app in the browser, then getting familiar with those tools will help you loads. Just keep in mind that React & React-Native isn't the same.

When you debug visuals, the best way is start at the top layer and work you way down. Color the elements & feel free to comment out elements to get you a clearer view of the problem. Keep digging down until you find the problem, don't be afraid to look into the source code of the packages you use, it often helps clarify (unexpected) behaviours.

You could try to replace

<View flex={1}> // applied a flex for the entire homepage

in Home.tsx with

<View flex="1 1 0">

Working example here (is your code with that line modified).

As for debugging I can only suggest what is already suggested on react native Debugging page. Have you tried React Developer Tools yet? In chrome you can also add it as an extension from this link.

I am not sure if there is any difference between chrome extension and the npm package but the extension was enough for me at least (for now).

The only problem is that I also struggled debugging on codesandbox since the extension is definitely not working on javascript online editors (but probably the npm package doesn't either for this specific case)

Try this - https://snack.expo.dev/fL0OgQ9uS

import React from 'react';
import { View, Image, StyleSheet,ScrollView,Text } from 'react-native';

const styles = StyleSheet.create({
  container: {
    paddingTop: 50,
    flex:1,
    backgroundColor:'aqua',
  },
  tinyLogo: {
    width: 200,
    height: 200,
  },
  header:{
    backgroundColor:'green',
    paddingBottom:20,
  },
  footer:{
    backgroundColor:'green',
    paddingTop:20,
  }
});

const DisplayAnImage = () => {
  return (

    <View style={styles.container}>
      <View style={styles.header}><Text>header</Text></View>
       <ScrollView>
        <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />
              <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />
              <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />
              <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />
              <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />
              <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />

              <Image
        style={styles.tinyLogo}
        source={require('@expo/snack-static/react-native-logo.png')}
      />
  
      </ScrollView>
      <View  style={styles.footer}><Text>footer</Text></View>
    </View>

  );
}

export default DisplayAnImage;