in-memory JPEG augmentations

[serycjon]

Hi, it seems JPEG augmentations are using temporary file on disk to do the JPEG compression:

imgaug/imgaug/augmenters/arithmetic.py

Line 1747 in 0101108

with tempfile.NamedTemporaryFile(mode="wb+", suffix=".jpg") as f:

This can be done in-memory (-> probably more efficiently) using io.BytesIO(). Something like the following:

import io
from PIL import Image
import numpy as np

pil_image = Image.fromarray(np_rgb_img)
buf = io.BytesIO()
pil_image.save(buf, format='JPEG', quality=0.25)
pil_image = Image.open(buf)
np_img_with_compression = np.asarray(pil_image)