Having a wierd issue I've never had before.  I have my image in Lux exactly how I want it with film response, exposure, lighting, gamma, etc.  It's a dark scene with lots of shadows and took a while to get it right.

I used file-->save and exit in lux, opened the png in photoshop to make it a forum friendly size and the image is much brighter and the lighting and shadow look nothing like they do in the lux window. 

Edit: Just tried opening it with Windows photo viewer and it looks fine, but I can't edit with that.