You can change the values into the main.py:
NB_STRING = 300
CANVAS_SIZE = 250
POP_SIZE = 100
NB_GENERATION = 100
STRING_WIDTH = 1
trying to recreate images with strings only...
generation 0 :
[...]
>> git clone https://github.com/samuel3105/Python-genetic-algorithm-_-String-art-portrait.git
>> cd ./Python-genetic-algorithm-_-String-art-portrait
>> python3 main.py