Support loading PNG & other image types from ByteTensors

[genixpro]

I would like to see functions like image.decompressJPG(tensor, [depth, tensortype]), except for PNG and other image types.

Preferably, a generic function which can load any image type. I don't want to save my image to a file just so I can use image.load

[nibrahim]

This does exist for PNG atleast. You can see it here https://github.com/torch/image/blob/master/init.lua#L181. I've used it too and can confirm that it works.