I've been thinking of uploading a couple of hypno-related CGs from visual novel, but I'm unsure what the best way to do it is. Have some concerns about flooding main page, but also don't think spamming parent post is the correct way either.

Valid concerns.

You can post them over time, one per page, add them to a pool as you do it. That would work! It would probably get more attention too.

And, 'couple' implies as much, but, just to be safe, be reasonable about the number of them! Fair use and all that~

Speaking of, definitely use a place you can buy the game as the source link.

Thanks for the advice. Also linking a steam page as a source sounds really funny so I'll do that.