You can use the ScreenSaverTool in Horizon Link Suite. It's not quite as easy as the app, and you have to use a USB flash drive to carry the images to the machine, but it shouldn't crash. What most likely happened is that the Janome app did something that no longer works in the latest version of iOS on your iPad. If you opted in to crash reporting, they will get a report on the crash. However with iOS 13 about to drop, they are most likely scrambling to get everything up to date. Look for an update to the ScreenSave app sometime in October or later.