Firefly in Poser 11 uses Gamma Correction where as it use to be a Pro only feature. Go into render settings and change the 2.2 to 1.0 if you don't want to correct the materials in the shader. Otherwise find the image map and change from Use Gamma value from Render Settings TO Custom Gamma value GC and change the value from 2.2 to 1.0. Before Poser 11 the non-Pro version did not have Gamma correction and when it was added a lot of image maps which were use to a value of 1.0 were all a sudden using 2.2. Mostly it works good for actual images, but messes with the transparency and changed the look.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13