image_mean = [0.485, 0.456, 0.406 ]
image_std = [0.229, 0.224, 0.225]

These are the mean and standard deviation used to normalize images during the model pre-training. These values are crucial
to replicate when doing inference or finetuning a pre-trained image model.
Instantiate the image processor from the same checkpoint as the model you want to finetune.

from transformers import AutoImageProcessor
checkpoint = "facebook/detr-resnet-50"
image_processor = AutoImageProcessor.from_pretrained(checkpoint)