Impact of input scale on the output in Retinaface

I have been utilizing the `retinaface_r50_v1` model and inputting images of size (640, 640), and the results have been consistently impressive. However, I'm curious to explore whether the outcome would improve if I were to omit resizing the images to (640, 640) and directly input them into the model. I'm uncertain about the potential impact of input scale on the output.

The issue names the retinaface_r50_v1 model and the current (640, 640) input size, but no files or tests. Start by locating that model's input preprocessing and inference entry point, then compare fixed-size and direct-image behavior. Done would require a documented, reproducible conclusion and a clearly scoped change target.

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