Training on unconditional image generation creates colorized images

### Describe the bug

Hi, I'm trying to follow the tutorial from unconditional image generation on my own dataset, and I'm getting weirdly colored images. I originally thought it was due to RGB/BGR channel order, but I've switched it around and got the same result. Do you have any suggestions of how to fix it?

### Reproduction

NA

### Logs

```shell

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### System Info

NA

### Who can help?

_No response_

Start with the unconditional image generation tutorial and compare its dataset preprocessing with the reporter’s own dataset, including the stated RGB/BGR concern. First obtain a reproducible example with concrete dataset and system details, since the issue provides none; done means identifying the cause of the colorized output and verifying a fix.

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