image viewer aspiring to be like edisplay (http://exactcode.com/opensource/exactimage/)
... but in Qt
... as http://en.pudn.com/Download/item/id/3295527.html is not quite there
... because https://github.com/cameronmott/QTImageDisplayApp came up short
... and I haven't checked all https://github.com/search?q=qtimageviewer
... and uses OpenCV to make things faster to deliver