SwiftUI・UIKit・AppKitでの画像処理の煩わしさを解消するためのヒント 👉 https://android.benigumo.com/20241010/swiftui-uikit-appkit/

AsyncImageEx.swift

import SwiftUI

struct Sample: View {
  @State private var data: Data = .init()

  private let urlStrings = [
    "https://i.imgur.com/05S3yYZ.png",
    "https://i.imgur.com/REuN9RR.png" // removed
  ]

  var body: some View {
    VStack {
      ForEach(urlStrings, id: \.self) { urlString in
        AsyncImageEx(
          urlString: urlString,
          of: .removed,
          with: .replace
        )
      }
    }
    .frame(width: 100)
    .padding()
  }
}

struct AsyncImageEx: View {
  var urlString: String
  var of: Image
  var with: Image

  var body: some View {
    AsyncImage(url: URL(string: urlString)!) { image in
      //if image == of {
      if image.pngData == of.pngData {
        with
          .resizable()
          .scaledToFit()
          .foregroundStyle(.gray)
      } else {
        image
          .resizable()
          .scaledToFit()
      }
    } placeholder: {
      ProgressView()
    }
  }
}

extension  Data {
  var image: Image {
    #if canImport(UIKit)
    let uiImage = UIImage(data: self) ?? UIImage()
    return Image(uiImage: uiImage)
    #else
    let nsImage = NSImage(data: self) ?? NSImage()
    return Image(nsImage: nsImage)
    #endif
  }
}

extension Image {
  static let removed = (
    (try? Data(contentsOf: URL(string: "https://i.imgur.com/removed.png")!)) ?? Data()
  ).image

  static let replace = Image(systemName: "xmark.circle.fill")

  @MainActor
  var pngData: Data {
    #if canImport(UIKit)
    if let uiImage = ImageRenderer(content: self).uiImage,
       let data = uiImage.pngData() {
      return data
    } else {
      return Data()
    }
    // return ImageRenderer(content: self).uiImage?.pngData() ?? Data()
    #else
    if let nsImage = ImageRenderer(content: self).nsImage,
       let cgImage = nsImage.cgImage(forProposedRect: nil, context: nil, hints: nil),
       let data = NSBitmapImageRep(cgImage: cgImage).representation(using: .png, properties: [:]) {
      return data
    } else {
      return Data()
    }
    #endif
  }
}

#Preview("Sample") {
  Sample()
}