This isn’t a problem and I don’t need answer fast ;). It’s just something I’ve noticed over the years. I have an iPhone 7+ and I’m a big fan of double tapping the home button to change between or exit applications. I’ve noticed that frequently a website I was looking at earlier but closed out of will be a sort of ghost image for a second when I switch back to safari but as soon as it maximizes it will change back to the thing I’m currently looking at, and I also see the same thing sometimes with photos or other applications. What exactly causes this and does an exorcism come into play at some point? Please say it does…
This is for the Air Pad, but it might be useful. https://discussions.apple.com/thread/8317494
Thanks but it’s not a “problem” or a shadow that remains it goes away I just want to know on a technical level why it happens at all.
I don’t use many Apple products, so I can only guess that it’s caused by caching (either in Safari or in video memory) or by an app that doesn’t fully close.
As you’ve surmised, this may be what you need.
The app switcher preview is managed by the application being backgrounded. The app receives a notification that it is being suspended, and the app can handle this any way the developer wants, such as by taking a screenshot of the app’s current display just before it is suspended. The app then sets the screenshot as the app preview image.
For some reason, Safari doesn’t always update its switcher preview, and I believe it’s because the page hasn’t fully loaded and that is a prerequisite for Safari to update the preview.
This is also why some apps, especially banking apps, display app splash screens instead of previews. The app sets its preview image to a static image for privacy reasons.