backend/utils/image.py

from PIL import Image
import torchvision.transforms as transforms

transform = transforms.Compose([
    transforms.Resize((224,224)),
    transforms.ToTensor(),
    transforms.Normalize([0.485,0.456,0.406],
                         [0.229,0.224,0.225])
])

def preprocess(image_bytes):
    image = Image.open(image_bytes).convert("RGB")
    return transform(image).unsqueeze(0)