What is Invoke AI?
Invoke AI is a sophisticated interface for Stable Diffusion that allows you to create graphics using a variety of SD models. One of the nicest aspects of Invoke AI is the "Unified Canvas" function, which allows you to modify within and around a picture using text prompts. The Unified Canvas allows you to outpaint your image to increase its resolution significantly, and it may also be used to add fine-tuned features to select sections of your image.
Invoke AI has produced a useful documentation guide for their product, which includes all of the information you need to set it up and get started. It is considerably easier to install than most other Stable Diffusion interfaces because it only requires one click.