First and foremost, the Insert SDK will never interfere with the regular behavior of an app. If insert content cannot be retrieved for whatever reason, the app will continue to function as normal.
The Insert SDK caches any image it downloads, so an image is downloaded once unless it changes or the cache expires. The images used for backgrounds and inline images should be as small as possible to avoid long download times.
Some of the inserts, such as Modify Text, are cached on the device to be ready immediately on app launch. These inserts will work regardless of network connection characteristics.