Is game cg allowed? if it allowed then on what circumstance?

Imagine I want to upload game cg of a paid eroge.

1. will it count as "commercially licensed anime or manga" since it not anime nor manga but commercially licensed?
2. will it count as paid content, since you technically have to pay for it? what if the website release a free cg as an example of the game will it still count?
3. is ripping cg legal? if it not will the screenshot of the game count as screencaps

Just to make sure that I will not get banned if I upload it.

To answer your primary question, yes, game cg is allowed, regardless of the game being a commercial product or not. See help:upload rules for a list of prohibited content, which does not include game cg.