SwiftUI strange behaviour with HStack

Question

As title says I cannot understand where is the problem in my layout.

I created a simple view called SmallCard

struct SmallCard: View {
    var image: Image
    var title: String
    
    var body: some View {
        VStack(spacing: 0.0) {
            self.image
                .resizable()
                .scaledToFit()
            
            ZStack {
                Color.white
                
                VStack(alignment: .leading) {
                    Text(self.title)
                        .padding([.vertical])
                }
                
            }
        }
        .rounded(radius: 10)
        .shadow(radius: 2.0)
    }
}

struct SmallCard_Previews: PreviewProvider {
    static var previews: some View {
        SmallCard(image: Image("img02"), title: "Card title")
    }
}

with this result

Then I created another view called TestExploreCards

struct TestExploreCards: View {
    var body: some View {
        ScrollView {
            HStack(alignment: .center, spacing: 8.0) {
                SmallCard(image: Image("img04"),
                                    title: "Card title 01")
                
                SmallCard(image: Image("img05"),
                                    title: "Card title 03")
            }
        }
    }
}

struct TestExploreCards_Previews: PreviewProvider {
    static var previews: some View {
        TestExploreCards()
    }
}

where I put two SmallCard to getbut instead I get

As you can see in the SmallCard preview Image is same width as the view below, but when I put in a HStack with another instance of SmallCard it isn't. I can't figure where is the error:\

Just to be clear, rounded is a View extension

extension View {
    func rounded(radius: CGFloat = 25.0) -> some View {
        self.clipShape(RoundedRectangle(cornerRadius: radius, style: .continuous))
    }
}

Answer 1

HStack filled the width but image was trying to fit the content by its proportion.

Here is the modified code:

struct SmallCard: View {
    var image: Image
    var title: String
    
    var body: some View {
        VStack(spacing: 0.0) {
            self.image
                .resizable()
                .scaledToFill()
            
            VStack(alignment: .leading) {
                Text(self.title)
                    .padding(.vertical)
                    .frame(maxWidth: .infinity)
            }
            .background(
                Color.white
            )
            
        }
        .frame(minHeight: 250.0)
        .rounded(radius: 10)
        .fixedSize(horizontal: false, vertical: true)
        .shadow(radius: 2.0)
    }
}

struct TestExploreCards: View {
    var body: some View {
        ScrollView {
            HStack(alignment: .center, spacing: 8.0) {
                SmallCard(image: Image("img04"),
                          title: "Card title 01")
                
                SmallCard(image: Image("img05"),
                          title: "Card title 03")
            }
        }
        .padding()
    }
}

struct TestExploreCards_Previews: PreviewProvider {
    static var previews: some View {
        TestExploreCards()
    }
}

extension View {
    func rounded(radius: CGFloat = 25.0) -> some View {
        self.clipShape(RoundedRectangle(cornerRadius: radius))
    }
}

Result: