feature request: render test image while training

[kthordarson]

It would be nice to follow the progress while training by rendering a sample image at X intervals while training a new model. For example at each num_steps_ckpt a sample image will be rendered.

[ghwatson]

You could easily use put this in the code in a few lines by using tf.summary.image (https://www.tensorflow.org/api_docs/python/tf/summary/image) Just look in the code at the other summaries. Keep in mind that saving images will make the tf.event files that get saved much larger.