Kingfisher/Sources/Documentation.docc/Topics/Topic_LowDataMode.md

Loading Image for Low Data Mode

Overview

From iOS 13, Apple allows user to choose to turn on [Low Data Mode] to save cellular and Wi-Fi usage. To respect this setting, you can provide an alternative (usually low-resolution) version of the image and Kingfisher will use that when Low Data Mode is enabled:

imageView.kf.setImage(
    with: highResolutionURL, 
    options: [.lowDataSource(.network(lowResolutionURL)]
)

If there is no network restriction applied by user, highResolutionURL will be used. Otherwise, when the device is under Low Data Mode and the highResolutionURL version is not hit in the cache, lowResolutionURL will be used.

Since .lowDataSource accept any Source parameter instead of only a URL, you can also pass in a local image provider to prevent any downloading task:

imageView.kf.setImage(
    with: highResolutionURL, 
    options: [
        .lowDataSource(
            .provider(LocalFileImageDataProvider(fileURL: localFileURL))
        )
    ]
)

If .lowDataSource option is not provided, the highResolutionURL will be always used, regardless of the Low Data Mode setting on the device.