ComfyUI is a powerful and modular stable diffusion GUI with a graph/nodes interface. It allows users to design and execute advanced stable diffusion pipelines with a flowchart-based interface. It supports SD1.x and SD2.x and offers many optimizations, such as re-executing only parts of the workflow that change between executions. It also supports loading checkpoints and safetensors models, and various upscaling models (ESRGAN, ESRGAN variants, SwinIR, Swin2SR, etc.). It can also save/load workflows as JSON files, and generate and load full workflows from PNG files.