The 'Portrait Relight' workflow in ComfyUI is designed to transform the lighting of a target image by using a reference image that provides the desired lighting conditions. This process is achieved through the use of the Qwen-Image-Edit model, which is adept at image editing tasks such as relighting while maintaining intricate details like edges. The workflow involves several critical nodes, including LoadImage, which imports the target and reference images, and SaveImage, which outputs the final relighted image. A unique aspect of this workflow is its ability to maintain specific details, such as the canny edge of an interior glass orb, ensuring that the structural integrity of the image is preserved even as lighting conditions change. This makes it particularly useful for applications where maintaining fine details is crucial.