treat image MAPS as a painted texture that applies to your figure . They must follow the UV MAP for the figure you are using. So a v3 texture wont fit V4 .

In Poser you can merge several images to make the texture. In Daz studio it needs (I think) to be one image , so you layer them in a paint program like Gimp or photoshop. There are sets of bodyhair brushes so you can paint your own , or you get  one already done from the marketplace .