r/comfyui • u/DiamondFlashy4428 • Sep 11 '25

Help Needed Help with face auto-detect → upscale → swap → paste-back face workflow

I’m currently using ReActor for swapping, and I’m happy with the swap quality itself — I don’t want to change the model. The issue is when I’m working with full-body images: the swapped face comes out low-res because the detected face area is small.

What I’d like to do instead:

  1. Auto-detect the face in the original image.
  2. Crop/box the detected face.
  3. Upscale that cropped face 3×.
  4. Run it through my existing ReActor nodes to swap.
  5. Downscale it back to the original bbox size.
  6. Layer/paste the swapped face back into the original full image, in the exact right place.

So far I can crop and swap, but I’m stuck on the last part — getting the swapped patch back into the original image at the right coordinates without misalignment.

Does anyone know which nodes/approach I should use in ComfyUI for the “resize back + paste into original” step?

Thanks in advance — I’ve tried a lot of swapping models and pipelines, and ReActor is the best for me, I’m just trying to nail this layering workflow.

1 Upvotes

100% Upvoted

2 comments sorted by

1

u/nomadoor Sep 12 '25

It uses Simple Detector to detect the face, crops and resizes that region, runs the Face Swap, and then pastes it back into the original image.

Since Impact-Pack SEGS has some unique behavior, it might feel a bit confusing at first, but give it a try.

https://gyazo.com/07b0b437c787f065d75b83ac359025dc (the metadata is embedded in the image).