Transform image to base64 string use PIL problem

[starsky0426]

from PIL import Image
from io import BytesIO
import base64

img = Image.open(file_name) # path to file
img_buffer = BytesIO()
img.save(img_buffer, format=img.format)
byte_data = img_buffer.getvalue()
base64_str = base64.b64encode(byte_data) # bytes
base64_str = base64_str.decode("utf-8") # str

As the code above in README, if we decode the base64_str back to PIL image, and compare with the image directly opened with Image.open(fillepath), they have minor differences.

we can compare them by converting images to numpy array like below:

image = Image.open(BytesIO(base64.urlsafe_b64decode(base64_str)))
diff = np.array(image) - np.array(Image.open(image_path))
print(np.max(diff))

The correct way to encode an image to base64 string is as below:

with open(image_path, 'rb') as f:
    base64_str = base64.b64encode(f.read()).decode('utf-8')
return base64_str