curl -X POST http://127.0.0.1:8188/upload/image -F 'image=@photo.png' -F 'type=input' -F 'overwrite=true'

Uploads photo.png into ComfyUI's input folder so workflows can reference it by filename, the API path behind img2img and inpainting jobs. The -F flags send multipart form fields: the file, the folder type, and overwrite behaviour. The response echoes the stored filename to use in your workflow JSON.