Does anyone know what software (or combination) dark silver is using for rendering his images?
Standard DAZ Studio which is free as was pointed out is what was most likely used. The models, props, etc. can get expensive. (If you want some tips on buying and on how to keep costs down I can post them.) Poser is another program that can handle most DAZ3D models. that is also commonly used.
DAZ3D originally started as a company that just made models for Poser and DAZ Studio got made as an alternative to Poser when it was believed years back that the company who owned and made Poser was going to fail. (The company was called Zygote and DAZ3D broke off from them to just focus on making Poser compatible content originally. Zygote is still around and they make 3D models used in the construction of medical instruments, medical text, and models for the medical fieald.)
The rendering systems are different between those 2 programs and you can do rendering with different render engines with certain plug-ins and also use other software to work with the figures.
One big thing with the renders in just about every 3D game is that the developers never learned basic lighting and that you often need to adjust material settings for a good looking render. DAZ Studio also had some problems a few years back as the rendering engine that it uses got a major change and a lot of texture and render settings would no longer render correctly for a lot of older content. You can do a good render without any Photoshop or similar graphics program touch up.
The majority of professional renders do get touched up in an editor.
One big tip I'll give to wrap this up is to get this book :
Figures, Characters and Avatars: The Official Guide to Using DAZ Studio to Create Beautiful Art, 1st Edition, by Les Pardew
The 1st edition of the physical book comes with a disk that has a lot of older expensive content. The full V4 & M4 Pro Bundles are on it and so is an older version of Carrara Pro, etc . DAZ's tech support will add those items to your DAZ Account if you contact them and send a email scan of your receipt. The serial key for Carrara and the Hexagon copy can be gotten by contact DAZ's support or going to the publishers website and looking for the supplemental downloads for the book.
The latter 2nd edition doesn't have the disk of goodies.