Stable-Diffusion-Android is an Android application that allows users to quickly and easily create images from text or other images.
Technically, it is a Stable-Diffusion client that connects to either your neural network instance (running on your server or Colab) or you can use AI Horde (a crowdsourced distributed cluster)
The app also includes a built-in gallery for storing AI-generated images, with export capabilities.
The download is available through F-droid
This app is quite nice, albeit somewhat minimalist, yet it gets the job done if you prefer not to use the web interface.