A change has been made to add support for loading local images in the background on iOS.
Traditionally an image was always loaded in the background when its path was a remote URL (i.e. "http://foo.com/123.png"), and in the foreground when it's a local path in the app directory (i.e. "123.png").
In most cases, this is the preferred behavior; remote images eventually appear when they've finished downloading asynchronously
(without blocking the UI), but local images appear immediately because they're loaded from the file system synchronously.
But for List blocks with local left/right/background images specified, this can cause the UI to stutter as the images are loaded
synchronously.  If you want to load local images in the background, you can turn them into URLs by prefixing the path with "file:".  For
In both of the cases above, the image will get loaded asynchronously.