Performance issue #12
Description
Hello, I found a performance issue in the definition of crack_captcha, Discuz/test.py, tf.argmax and tf.reshape will be created repeatedly during the program execution. It will add extra node in the graph(tensorflow 1.x). I think it should be created before the loo in the crack_captcha.
Looking forward to your reply. Btw, I am very glad to create a PR to fix it if you are too busy.