Improve PNG compression in add_image_summary (#995)
Improve PNG compression in add_image_summary (#995)

OpenCV does not fully compress PNGs by default. This additional parameter tells OpenCV to use the maximum PNG compression level for encoding images. This should reduce the size of saved Tensorboard images particularly for highly compressible domains such as segmentations.
ppwwyyxx/tensorpack,ppwwyyxx/tensorpack