Fliff vs Dark Preview Camera

With Fliff you can convert formats of image files or scale them. You can load images from the clipboard, the Photos app, the Files app or from the camera. The converted images files can be saved to file system and to the camera roll and can be copied to the clipboard or shared. You can preview them in order to check the file size and the quality, espicially when using compression. Fliff can also be called from the Share menu in other apps that provide images. Furthermore Fliff is also a photo editing extension, i.e. you can use it as a plugin in the edit mode of the Photos app. 
This app is freeware. It comes with absolutely no warranty. Use it at your own risk!

Dark Preview Camera is a camera app designed to let you take photos and videos while keeping your screen brightness low. At night or in dark environments, your iPhone display can feel surprisingly bright. With Dark Preview Camera, you can reduce the screen brightness while using the camera, helping you keep the light from your display to a minimum while taking photos or recording videos. Screen brightness can be adjusted to suit your surroundings. [Simple Shooting Controls] Just tap the screen to start shooting. When you’re finished, double-tap the screen to stop. Simple controls make it easy to start and stop shooting in the dark. On iPhone models that support Camera Control, you can also use Camera Control to shoot without having to interact with the screen as much. [Main Features] * Shoot while keeping screen brightness low * Adjustable screen brightness * Tap the screen to shoot * Double-tap to stop shooting * Shoot using Camera Control * Photo and video capture * Front and rear camera switching * Zoom * Grid display * Level * Save location information with photos Ideal for nighttime, dark rooms, or anywhere you want to minimize the light coming from your screen.