SwiftUI: How to blend between UIImages without pulsating/pumping effect?

I want to smootlhy blend two or more UIImages without pulsating/pumping effect but cannot achieve this.

I have created a simple example code to visualize my issue. Two UIImages with exactly the same content ("gear") are initialized. The images are then manipulated via "func resizeImage()" with:

UIGraphicsBeginImageContext() defer { UIGraphicsEndImageContext() } draw(in: CGRect())

This custom draw: (in:) is important for me as in my app there is a lot of custom drawing logic.

In the body I use a PhaseAnimator to animate through the different stages of my custom animation.

The result is always a pulsating/pumping effect which is unwanted. If the shape of two blended UIImages is exactly the same, there should not be any noticeable difference, especially no intensity change.

How to get a smooth blend without pulsating/pumping effect?

Any help appreciated.

import SwiftUI

struct ContentView: View {
    @State var widgetSize: CGFloat = 128
    let img1 = UIImage(systemName: "gear")!
    let img2 = UIImage(systemName: "gear")!
    
    func resizeImage(image: UIImage, newWidth: CGFloat) -> UIImage {
        let scale = newWidth / image.size.width
        let newHeight = image.size.height * scale
        UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight))
        image.draw(in: CGRectMake(0, 0, newWidth, newHeight))
        guard let newImage = UIGraphicsGetImageFromCurrentImageContext() else { return UIImage(systemName: "questionmark")! }
        UIGraphicsEndImageContext()
        return newImage
    }
    
    var body: some View {
        PhaseAnimator([1, 2]) { phase in

            // This is just for demonstration purposes
            // I have two or more UIImages that I want to smootlhy blend
            // The UIImages are created with image.draw
            // the result is a pulsating animation but I would expect
            // a smooth blend over with no noticable change when there are two
            // UIImages with identical content

            let i1 = self.resizeImage(image: img1, newWidth: widgetSize)
            let i2 = self.resizeImage(image: img2, newWidth: widgetSize)
            
            VStack {
                Image(uiImage: phase == 1 ? i1 : i2)
                    .renderingMode(.template)
                    .foregroundStyle(.white)
                    .background(.black)
                Spacer()
            }
        }
    }
}


#Preview {
    ContentView()
}