Hello, what I can tell you so far is, that pictures like this can only be achieved when you take care about the following things:

1. lights: the poser default lights will hardly give you such achievments, you will need to build your own lights or if you are new to that buy some. I prefer IBL (image based lightening) and have already seen plenty of good looking stuff here on Rendero which seems to have a good quality.

2. skin and shaders: A high resolution texture without shaders will not give you good results. You can buy characters which already have shaders (as most of them have today) or buy add on scripts like the vendor face_off has to shade your skin by yourself.  

3. render settings: what you can achieve depends MUCH on your hardware. You can't expect to render a large image in high quality when your computer is too slow etc. If you are a beginner I would hint you to try to raise your render settings and try them out until you are satisfied. 

I have never used things like render studio. Actually Poser has everything you need (render-wise) to produce images like that. 

I hope I could help you, if you have more questions, just ask.