Bring your figure onto the stage, then go into the Material room. Grab the Eyedropper tool and click on a body part/hair/etc/material you wish to alter...

To change the map you will click on image source (see attached)

Once that is done you have the option to change the Gamma value for that image map and/or change out that map too (see attached)

In your Render settings you will see a box for Gamma Value, set that to 2.2

For all of your image maps the default value is already set to 2.2, for all of your bump, displace, transparency/etc maps you want to set those to 1. Why? Because you are telling Poser in your renders settings to make everything gamma 2.2 but you don't want grey/black/white value maps being adjusted to 2.2, you want those to stay at 1.

Hope this helps.

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