I can understand that frustration.  Recently, I loaded an old model into Poser and discovered that the image_maps were not Gamma Corrected also with no displacement.  A dungeon scene with stone walls.  I Gc'ed the maps in Photoshop, and once I brought them into Pose, created grayscale displacement maps by plugging the Image_maps into a hsv node.  The saturation value was turned down to 0.  This node was plugged into the displacement channel.  Upon rendering, I had to remind myself to turn on displacement in the render settings.