How to train an image dataset in TensorFlow?
If you are interested in training tensorflow model for image recognition in general, it is a good idea to go through tensorflow tutorials on MNIST:

https://www.tensorflow.org/get_started/mnist/beginners
https://www.tensorflow.org/get_started/mnist/pros

If you want to collect the data yourself and train model on it, here is something which could be interesting: https://digits-draw-recognize.herokuapp.com/

This is my site with handwritten digit recognition. I have collected dataset by myself - I drew ~1k digits and processed the data. After this I trained two models, one of them is CNN in Tensorflow. And these models train on the new images drawn by people. You can find some description of functionality on this site.