Are using CGs from other creations prohibited?

[Snowflower]

Due to the fact that I am using bass images for my first VN, I do not have original CGs.
However, I've collected ones that others have used before in their work.
I don't know who the real artists are aside from one since they were from portal sites with CG collects.
Before I publicize my VN, i would like to know whether or not if it's okay for me to use such CGs. I am not using the VN for a commercial use, just for fun
however, I don't want to get in some sort of trouble with the law, you know?

Oh, and the only project that I know where the CGs come from is starry sky...
I'm not claim them as my own. I will give credit accordingly?

please let me know

[okonomiyaki]

It's still technically against copyright law. Whether you'll be sued over it is a different story. I wouldn't do it because it's kind of a rotten thing to do.

[Elze]

Oh crap, don't do it! Most of these cg collecting sites are a collection of pictures uploaded by people who don't even know where the original images come from. That means they have zero rights to the images. If you use some popular images from known artists on DA or Pixiv, prepare to be crushed under a stampede of raging fans of the artists. DDD: It won't be pretty.
I'd advice you against it unless you know where the images are from and request for permission to use them.

[gekiganwing]

The person who created "Final Week" freely admits that the character images and backgrounds in his game are from an untranslated game. (His planned game Project Memoria should have original art.) There may be others which are not fangames that use copyrighted images, though I can't think of any.

[Aleema]

Well, it's not prohibited in that PyTom will delete your game (though it is prohibited in that it's illegal), it's just not cool for people who've already seen the CGs from the game they're already from (I'm about to play starry sky, so it would spoil it for me) and for those who know it's not yours and can't respect that. You're already not using anything you've made, so ...

I wouldn't make a habit of it. Eventually, making your own games should mean you invest something into them (the visual part of a visual novel). Otherwise you should stick to stock resources only, because that's cheating. =P

[PyTom]

More accurately: I wait until the creator complains to delete something like this - except for really obvious piracy of a game with no redeeming value whatsoever. (I'd generally allow a Date Warp fan-game, unless papillion asks me to remove it - but I wouldn't allow someone to post a pirate copy of Date Warp.)

[sake-bento]

Date Warp is actually a pretty good example of the situation you're in right now. The character sprites were premade by someone else and legal to use (like using the sprites from Bass), but papillion hired an artist to do all the CGs for the game. That way it was still legal. If your game is near completion, I'm sure you could find an artist who wouldn't mind drawing a few CGs of the characters.