Not generate the same image with the same key problem.

[zencore-dobetter]

captcha/views.py:50

random.seed(key) # Do not generate different images for the same key

This random.seed(key) can NOT ensure to generate the same images at high concurrent requests scenario.
Suggest to use private_random_generator = random.Random(key) to create a function private random generator, and use private_random_generator.choices and private_random_generator.randrange in the image generate function.

[zencore-dobetter]

And needs to pass the private_random_generator to the noise_functions and maybe also filter_functions.