我尝试在我的应用程序中添加一个启动画面，但它不起作用（既不是来自Safari，也不是来自主屏幕）。
<meta name="viewport" content="initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"/>
<!-- Startup images -->
<!-- iOS iPad (retina, portrait) -->
<link rel="apple-touch-startup-image" media="(device-width: 1536px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 2)" href="images/apple-touch-startup-image-1536x2008.png">
<!-- iOS iPad (retina, landscape) -->
<link rel="apple-touch-startup-image" media="(device-width: 1536px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 2)" href="images/apple-touch-startup-image-1496x2048.png">
<!-- iOS iPad (portrait) -->
<link rel="apple-touch-startup-image" media="(device-width: 768px) and (orientation: portrait) and (-webkit-device-pixel-ratio: 1)" href="images/apple-touch-startup-image-768x1004.png">
<!-- iOS iPad (landscape) -->
<link rel="apple-touch-startup-image" media="(device-width: 768px) and (orientation: landscape) and (-webkit-device-pixel-ratio: 1)" href="images/apple-touch-startup-image-748x1024.png">
我在带有视网膜显示屏的iPad上打开它。所有图像均可访问，并通常通过直接链接加载。所有风景图像均为纵向格式，并顺时针旋转90度。我也尝试将视网膜的“宽度”设置为2048，没有运气。
我错过了什么吗？
使用的来源：
Mulitple "apple-touch-startup-image" resolutions for iOS web app (esp. for iPad)?
Is there an equivalent apple-touch-startup-image for the IPAD?
https://miguelmota.com/blog/iphone-and-ipad-web-app-startup-images/