If you are seeing images that are saving at a resolution on your device, this can be caused by a slow cellular or WiFi connection. You need to wait for the high-resolution wallpaper to download to your device from our servers before saving the wallpaper.
When you open a pack, the app downloads a low-resolution thumbnail of each wallpaper for quick browsing and once you select a wallpaper, it'll download the high-resolution image. This cuts down on server load, and saves you cellular bandwidth and data charges as well! Win-Win!
If you are in an area where you have slow network, you'll need to wait just a little bit longer for the wallpaper to download.