The Game: No, Those Hundos Ain't Mine ... I Don't Flash My Own Cash

The guy who says The Game ripped off his pic of $300k in hard cash ... says he's ready to help the rapper make stacks of his own, but Game's telling the guy to hit the bricks.

Timothy Sykes is calling out Game for reposting his drawer full of money shot without crediting him on Instagram. He tells us he found out when friends started tagging him on the photo ... which Sykes originally posted 4 months ago.

Still, Sykes says no hard feelings, and he's willing to teach Game the stock market tricks he used to turn $12k worth of bar mitzvah loot into $4.35 million!

Game thinks it's ridiculous Sykes got miffed at all. A source tells us Game is pointing out the post clearly says, "Mood" ... and he never claimed the shot was his, but he has plenty of his own dough to post.

As for Sykes' stock tips? We're told he says, "No one can show me shit. I'm rich bitchhhhhhhh!!"